diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/Changes | 10 | ||||
| -rw-r--r-- | Documentation/CodingStyle | 21 | ||||
| -rw-r--r-- | Documentation/DocBook/kernel-hacking.tmpl | 2 | ||||
| -rw-r--r-- | Documentation/SubmittingPatches | 86 | ||||
| -rw-r--r-- | Documentation/cciss.txt | 4 | ||||
| -rw-r--r-- | Documentation/dell_rbu.txt | 18 | ||||
| -rw-r--r-- | Documentation/device-mapper/snapshot.txt | 73 | ||||
| -rw-r--r-- | Documentation/dontdiff | 1 | ||||
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 9 | ||||
| -rw-r--r-- | Documentation/filesystems/relayfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/ia64/mca.txt | 194 | ||||
| -rw-r--r-- | Documentation/kdump/kdump.txt | 11 | ||||
| -rw-r--r-- | Documentation/keys.txt | 74 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | Documentation/oops-tracing.txt | 25 | ||||
| -rw-r--r-- | Documentation/pm.txt | 6 | ||||
| -rw-r--r-- | Documentation/sound/alsa/ALSA-Configuration.txt | 124 | ||||
| -rw-r--r-- | Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl | 10 | ||||
| -rw-r--r-- | Documentation/sparse.txt | 4 | ||||
| -rw-r--r-- | Documentation/usb/URB.txt | 74 |
20 files changed, 619 insertions, 139 deletions
diff --git a/Documentation/Changes b/Documentation/Changes index 5eaab0441d7..27232be26e1 100644 --- a/Documentation/Changes +++ b/Documentation/Changes @@ -237,6 +237,12 @@ udev udev is a userspace application for populating /dev dynamically with only entries for devices actually present. udev replaces devfs. +FUSE +---- + +Needs libfuse 2.4.0 or later. Absolute minimum is 2.3.0 but mount +options 'direct_io' and 'kernel_cache' won't work. + Networking ========== @@ -390,6 +396,10 @@ udev ---- o <http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev.html> +FUSE +---- +o <http://sourceforge.net/projects/fuse> + Networking ********** diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle index 22e5f9036f3..eb7db3c1922 100644 --- a/Documentation/CodingStyle +++ b/Documentation/CodingStyle @@ -410,7 +410,26 @@ Kernel messages do not have to be terminated with a period. Printing numbers in parentheses (%d) adds no value and should be avoided. - Chapter 13: References + Chapter 13: Allocating memory + +The kernel provides the following general purpose memory allocators: +kmalloc(), kzalloc(), kcalloc(), and vmalloc(). Please refer to the API +documentation for further information about them. + +The preferred form for passing a size of a struct is the following: + + p = kmalloc(sizeof(*p), ...); + +The alternative form where struct name is spelled out hurts readability and +introduces an opportunity for a bug when the pointer variable type is changed +but the corresponding sizeof that is passed to a memory allocator is not. + +Casting the return value which is a void pointer is redundant. The conversion +from void pointer to any other pointer type is guaranteed by the C programming +language. + + + Chapter 14: References The C Programming Language, Second Edition by Brian W. Kernighan and Dennis M. Ritchie. diff --git a/Documentation/DocBook/kernel-hacking.tmpl b/Documentation/DocBook/kernel-hacking.tmpl index 6367bba32d2..582032eea87 100644 --- a/Documentation/DocBook/kernel-hacking.tmpl +++ b/Documentation/DocBook/kernel-hacking.tmpl @@ -1105,7 +1105,7 @@ static struct block_device_operations opt_fops = { </listitem> <listitem> <para> - Function names as strings (__func__). + Function names as strings (__FUNCTION__). </para> </listitem> <listitem> diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 7f43b040311..237d54c44bc 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -301,8 +301,84 @@ now, but you can do this to mark internal company procedures or just point out some special detail about the sign-off. +12) The canonical patch format -12) More references for submitting patches +The canonical patch subject line is: + + Subject: [PATCH 001/123] subsystem: summary phrase + +The canonical patch message body contains the following: + + - A "from" line specifying the patch author. + + - An empty line. + + - The body of the explanation, which will be copied to the + permanent changelog to describe this patch. + + - The "Signed-off-by:" lines, described above, which will + also go in the changelog. + + - A marker line containing simply "---". + + - Any additional comments not suitable for the changelog. + + - The actual patch (diff output). + +The Subject line format makes it very easy to sort the emails +alphabetically by subject line - pretty much any email reader will +support that - since because the sequence number is zero-padded, +the numerical and alphabetic sort is the same. + +The "subsystem" in the email's Subject should identify which +area or subsystem of the kernel is being patched. + +The "summary phrase" in the email's Subject should concisely +describe the patch which that email contains. The "summary +phrase" should not be a filename. Do not use the same "summary +phrase" for every patch in a whole patch series. + +Bear in mind that the "summary phrase" of your email becomes +a globally-unique identifier for that patch. It propagates +all the way into the git changelog. The "summary phrase" may +later be used in developer discussions which refer to the patch. +People will want to google for the "summary phrase" to read +discussion regarding that patch. + +A couple of example Subjects: + + Subject: [patch 2/5] ext2: improve scalability of bitmap searching + Subject: [PATCHv2 001/207] x86: fix eflags tracking + +The "from" line must be the very first line in the message body, +and has the form: + + From: Original Author <author@example.com> + +The "from" line specifies who will be credited as the author of the +patch in the permanent changelog. If the "from" line is missing, +then the "From:" line from the email header will be used to determine +the patch author in the changelog. + +The explanation body will be committed to the permanent source +changelog, so should make sense to a competent reader who has long +since forgotten the immediate details of the discussion that might +have led to this patch. + +The "---" marker line serves the essential purpose of marking for patch +handling tools where the changelog message ends. + +One good use for the additional comments after the "---" marker is for +a diffstat, to show what files have changed, and the number of inserted +and deleted lines per file. A diffstat is especially useful on bigger +patches. Other comments relevant only to the moment or the maintainer, +not suitable for the permanent changelog, should also go here. + +See more details on the proper patch format in the following +references. + + +13) More references for submitting patches Andrew Morton, "The perfect patch" (tpp). <http://www.zip.com.au/~akpm/linux/patches/stuff/tpp.txt> @@ -310,6 +386,14 @@ Andrew Morton, "The perfect patch" (tpp). Jeff Garzik, "Linux kernel patch submission format." <http://linux.yyz.us/patch-format.html> +Greg KH, "How to piss off a kernel subsystem maintainer" + <http://www.kroah.com/log/2005/03/31/> + +Kernel Documentation/CodingStyle + <http://sosdg.org/~coywolf/lxr/source/Documentation/CodingStyle> + +Linus Torvald's mail on the canonical patch format: + <http://lkml.org/lkml/2005/4/7/183> ----------------------------------- diff --git a/Documentation/cciss.txt b/Documentation/cciss.txt index c8f9a73111d..68a711fb82c 100644 --- a/Documentation/cciss.txt +++ b/Documentation/cciss.txt @@ -17,7 +17,9 @@ This driver is known to work with the following cards: * SA P600 * SA P800 * SA E400 - * SA E300 + * SA P400i + * SA E200 + * SA E200i If nodes are not already created in the /dev/cciss directory, run as root: diff --git a/Documentation/dell_rbu.txt b/Documentation/dell_rbu.txt index bcfa5c35036..95d7f62e4db 100644 --- a/Documentation/dell_rbu.txt +++ b/Documentation/dell_rbu.txt @@ -13,6 +13,8 @@ the BIOS on Dell servers (starting from servers sold since 1999), desktops and notebooks (starting from those sold in 2005). Please go to http://support.dell.com register and you can find info on OpenManage and Dell Update packages (DUP). +Libsmbios can also be used to update BIOS on Dell systems go to +http://linux.dell.com/libsmbios/ for details. Dell_RBU driver supports BIOS update using the monilothic image and packetized image methods. In case of moniolithic the driver allocates a contiguous chunk @@ -22,8 +24,8 @@ would place each packet in contiguous physical memory. The driver also maintains a link list of packets for reading them back. If the dell_rbu driver is unloaded all the allocated memory is freed. -The rbu driver needs to have an application which will inform the BIOS to -enable the update in the next system reboot. +The rbu driver needs to have an application (as mentioned above)which will +inform the BIOS to enable the update in the next system reboot. The user should not unload the rbu driver after downloading the BIOS image or updating. @@ -42,9 +44,11 @@ In case of packet mechanism the single memory can be broken in smaller chuks of contiguous memory and the BIOS image is scattered in these packets. By default the driver uses monolithic memory for the update type. This can be -changed to contiguous during the driver load time by specifying the load +changed to packets during the driver load time by specifying the load parameter image_type=packet. This can also be changed later as below echo packet > /sys/devices/platform/dell_rbu/image_type +Also echoing either mono ,packet or init in to image_type will free up the +memory allocated by the driver. Do the steps below to download the BIOS image. 1) echo 1 > /sys/class/firmware/dell_rbu/loading @@ -53,9 +57,13 @@ Do the steps below to download the BIOS image. The /sys/class/firmware/dell_rbu/ entries will remain till the following is done. -echo -1 > /sys/class/firmware/dell_rbu/loading - +echo -1 > /sys/class/firmware/dell_rbu/loading. Until this step is completed the drivr cannot be unloaded. +If an user by accident executes steps 1 and 3 above without executing step 2; +it will make the /sys/class/firmware/dell_rbu/ entries to disappear. +The entries can be recreated by doing the following +echo init > /sys/devices/platform/dell_rbu/image_type +NOTE: echoing init in image_type does not change it original value. Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to read back the image downloaded. This is useful in case of packet update diff --git a/Documentation/device-mapper/snapshot.txt b/Documentation/device-mapper/snapshot.txt new file mode 100644 index 00000000000..dca274ff400 --- /dev/null +++ b/Documentation/device-mapper/snapshot.txt @@ -0,0 +1,73 @@ +Device-mapper snapshot support +============================== + +Device-mapper allows you, without massive data copying: + +*) To create snapshots of any block device i.e. mountable, saved states of +the block device which are also writable without interfering with the +original content; +*) To create device "forks", i.e. multiple different versions of the +same data stream. + + +In both cases, dm copies only the chunks of data that get changed and +uses a separate copy-on-write (COW) block device for storage. + + +There are two dm targets available: snapshot and snapshot-origin. + +*) snapshot-origin <origin> + +which will normally have one or more snapshots based on it. +You must create the snapshot-origin device before you can create snapshots. +Reads will be mapped directly to the backing device. For each write, the +original data will be saved in the <COW device> of each snapshot to keep +its visible content unchanged, at least until the <COW device> fills up. + + +*) snapshot <origin> <COW device> <persistent?> <chunksize> + +A snapshot is created of the <origin> block device. Changed chunks of +<chunksize> sectors will be stored on the <COW device>. Writes will +only go to the <COW device>. Reads will come from the <COW device> or +from <origin> for unchanged data. <COW device> will often be +smaller than the origin and if it fills up the snapshot will become +useless and be disabled, returning errors. So it is important to monitor +the amount of free space and expand the <COW device> before it fills up. + +<persistent?> is P (Persistent) or N (Not persistent - will not survive +after reboot). + + +How this is used by LVM2 +======================== +When you create the first LVM2 snapshot of a volume, four dm devices are used: + +1) a device containing the original mapping table of the source volume; +2) a device used as the <COW device>; +3) a "snapshot" device, combining #1 and #2, which is the visible snapshot + volume; +4) the "original" volume (which uses the device number used by the original + source volume), whose table is replaced by a "snapshot-origin" mapping + from device #1. + +A fixed naming scheme is used, so with the following commands: + +lvcreate -L 1G -n base volumeGroup +lvcreate -L 100M --snapshot -n snap volumeGroup/base + +we'll have this situation (with volumes in above order): + +# dmsetup table|grep volumeGroup + +volumeGroup-base-real: 0 2097152 linear 8:19 384 +volumeGroup-snap-cow: 0 204800 linear 8:19 2097536 +volumeGroup-snap: 0 2097152 snapshot 254:11 254:12 P 16 +volumeGroup-base: 0 2097152 snapshot-origin 254:11 + +# ls -lL /dev/mapper/volumeGroup-* +brw------- 1 root root 254, 11 29 ago 18:15 /dev/mapper/volumeGroup-base-real +brw------- 1 root root 254, 12 29 ago 18:15 /dev/mapper/volumeGroup-snap-cow +brw------- 1 root root 254, 13 29 ago 18:15 /dev/mapper/volumeGroup-snap +brw------- 1 root root 254, 10 29 ago 18:14 /dev/mapper/volumeGroup-base + diff --git a/Documentation/dontdiff b/Documentation/dontdiff index 96bea278bbf..24adfe9af3c 100644 --- a/Documentation/dontdiff +++ b/Documentation/dontdiff @@ -55,6 +55,7 @@ aic7*seq.h* aicasm aicdb.h* asm +asm-offsets.* asm_offsets.* autoconf.h* bbootsect diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 784e08c1c80..b67189a8d8d 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -17,15 +17,6 @@ Who: Greg Kroah-Hartman <greg@kroah.com> --------------------------- -What: io_remap_page_range() (macro or function) -When: September 2005 -Why: Replaced by io_remap_pfn_range() which allows more memory space - addressabilty (by using a pfn) and supports sparc & sparc64 - iospace as part of the pfn. -Who: Randy Dunlap <rddunlap@osdl.org> - ---------------------------- - What: RAW driver (CONFIG_RAW_DRIVER) When: December 2005 Why: declared obsolete since kernel 2.6.3 diff --git a/Documentation/filesystems/relayfs.txt b/Documentation/filesystems/relayfs.txt index d24e1b0d4f3..d803abed29f 100644 --- a/Documentation/filesystems/relayfs.txt +++ b/Documentation/filesystems/relayfs.txt @@ -15,7 +15,7 @@ retrieve the data as it becomes available. The format of the data logged into the channel buffers is completely up to the relayfs client; relayfs does however provide hooks which -allow clients to impose some stucture on the buffer data. Nor does +allow clients to impose some structure on the buffer data. Nor does relayfs implement any form of data filtering - this also is left to the client. The purpose is to keep relayfs as simple as possible. diff --git a/Documentation/ia64/mca.txt b/Documentation/ia64/mca.txt new file mode 100644 index 00000000000..a71cc6a67ef --- /dev/null +++ b/Documentation/ia64/mca.txt @@ -0,0 +1,194 @@ +An ad-hoc collection of notes on IA64 MCA and INIT processing. Feel +free to update it with notes about any area that is not clear. + +--- + +MCA/INIT are completely asynchronous. They can occur at any time, when +the OS is in any state. Including when one of the cpus is already +holding a spinlock. Trying to get any lock from MCA/INIT state is +asking for deadlock. Also the state of structures that are protected +by locks is indeterminate, including linked lists. + +--- + +The complicated ia64 MCA process. All of this is mandated by Intel's +specification for ia64 SAL, error recovery and and unwind, it is not as +if we have a choice here. + +* MCA occurs on one cpu, usually due to a double bit memory error. + This is the monarch cpu. + +* SAL sends an MCA rendezvous interrupt (which is a normal interrupt) + to all the other cpus, the slaves. + +* Slave cpus that receive the MCA interrupt call down into SAL, they + end up spinning disabled while the MCA is being serviced. + +* If any slave cpu was already spinning disabled when the MCA occurred + then it cannot service the MCA interrupt. SAL waits ~20 seconds then + sends an unmaskable INIT event to the slave cpus that have not + already rendezvoused. + +* Because MCA/INIT can be delivered at any time, including when the cpu + is down in PAL in physical mode, the registers at the time of the + event are _completely_ undefined. In particular the MCA/INIT + handlers cannot rely on the thread pointer, PAL physical mode can + (and does) modify TP. It is allowed to do that as long as it resets + TP on return. However MCA/INIT events expose us to these PAL + internal TP changes. Hence curr_task(). + +* If an MCA/INIT event occurs while the kernel was running (not user + space) and the kernel has called PAL then the MCA/INIT handler cannot + assume that the kernel stack is in a fit state to be used. Mainly + because PAL may or may not maintain the stack pointer internally. + Because the MCA/INIT handlers cannot trust the kernel stack, they + have to use their own, per-cpu stacks. The MCA/INIT stacks are + preformatted with just enough task state to let the relevant handlers + do their job. + +* Unlike most other architectures, the ia64 struct task is embedded in + the kernel stack[1]. So switching to a new kernel stack means that + we switch to a new task as well. Because various bits of the kernel + assume that current points into the struct task, switching to a new + stack also means a new value for current. + +* Once all slaves have rendezvoused and are spinning disabled, the + monarch is entered. The monarch now tries to diagnose the problem + and decide if it can recover or not. + +* Part of the monarch's job is to look at the state of all the other + tasks. The only way to do that on ia64 is to call the unwinder, + as mandated by Intel. + +* The starting point for the unwind depends on whether a task is + running or not. That is, whether it is on a cpu or is blocked. The + monarch has to determine whether or not a task is on a cpu before it + knows how to start unwinding it. The tasks that received an MCA or + INIT event are no longer running, they have been converted to blocked + tasks. But (and its a big but), the cpus that received the MCA + rendezvous interrupt are still running on their normal kernel stacks! + +* To distinguish between these two cases, the monarch must know which + tasks are on a cpu and which are not. Hence each slave cpu that + switches to an MCA/INIT stack, registers its new stack using + set_curr_task(), so the monarch can tell that the _original_ task is + no longer running on that cpu. That gives us a decent chance of + getting a valid backtrace of the _original_ task. + +* MCA/INIT can be nested, to a depth of 2 on any cpu. In the case of a + nested error, we want diagnostics on the MCA/INIT handler that + failed, not on the task that was originally running. Again this + requires set_curr_task() so the MCA/INIT handlers can register their + own stack as running on that cpu. Then a recursive error gets a + trace of the failing handler's "task". + +[1] My (Keith Owens) original design called for ia64 to separate its + struct task and the kernel stacks. Then the MCA/INIT data would be + chained stacks like i386 interrupt stacks. But that required + radical surgery on the rest of ia64, plus extra hard wired TLB + entries with its associated performance degradation. David + Mosberger vetoed that approach. Which meant that separate kernel + stacks meant separate "tasks" for the MCA/INIT handlers. + +--- + +INIT is less complicated than MCA. Pressing the nmi button or using +the equivalent command on the management console sends INIT to all +cpus. SAL picks one one of the cpus as the monarch and the rest are +slaves. All the OS INIT handlers are entered at approximately the same +time. The OS monarch prints the state of all tasks and returns, after +which the slaves return and the system resumes. + +At least that is what is supposed to happen. Alas there are broken +versions of SAL out there. Some drive all the cpus as monarchs. Some +drive them all as slaves. Some drive one cpu as monarch, wait for that +cpu to return from the OS then drive the rest as slaves. Some versions +of SAL cannot even cope with returning from the OS, they spin inside +SAL on resume. The OS INIT code has workarounds for some of these +broken SAL symptoms, but some simply cannot be fixed from the OS side. + +--- + +The scheduler hooks used by ia64 (curr_task, set_curr_task) are layer +violations. Unfortunately MCA/INIT start off as massive layer +violations (can occur at _any_ time) and they build from there. + +At least ia64 makes an attempt at recovering from hardware errors, but +it is a difficult problem because of the asynchronous nature of these +errors. When processing an unmaskable interrupt we sometimes need +special code to cope with our inability to take any locks. + +--- + +How is ia64 MCA/INIT different from x86 NMI? + +* x86 NMI typically gets delivered to one cpu. MCA/INIT gets sent to + all cpus. + +* x86 NMI cannot be nested. MCA/INIT can be nested, to a depth of 2 + per cpu. + +* x86 has a separate struct task which points to one of multiple kernel + stacks. ia64 has the struct task embedded in the single kernel + stack, so switching stack means switching task. + +* x86 does not call the BIOS so the NMI handler does not have to worry + about any registers having changed. MCA/INIT can occur while the cpu + is in PAL in physical mode, with undefined registers and an undefined + kernel stack. + +* i386 backtrace is not very sensitive to whether a process is running + or not. ia64 unwind is very, very sensitive to whether a process is + running or not. + +--- + +What happens when MCA/INIT is delivered what a cpu is running user +space code? + +The user mode registers are stored in the RSE area of the MCA/INIT on +entry to the OS and are restored from there on return to SAL, so user +mode registers are preserved across a recoverable MCA/INIT. Since the +OS has no idea what unwind data is available for the user space stack, +MCA/INIT never tries to backtrace user space. Which means that the OS +does not bother making the user space process look like a blocked task, +i.e. the OS does not copy pt_regs and switch_stack to the user space +stack. Also the OS has no idea how big the user space RSE and memory +stacks are, which makes it too risky to copy the saved state to a user +mode stack. + +--- + +How do we get a backtrace on the tasks that were running when MCA/INIT +was delivered? + +mca.c:::ia64_mca_modify_original_stack(). That identifies and +verifies the original kernel stack, copies the dirty registers from +the MCA/INIT stack's RSE to the original stack's RSE, copies the +skeleton struct pt_regs and switch_stack to the original stack, fills +in the skeleton structures from the PAL minstate area and updates the +original stack's thread.ksp. That makes the original stack look +exactly like any other blocked task, i.e. it now appears to be +sleeping. To get a backtrace, just start with thread.ksp for the +original task and unwind like any other sleeping task. + +--- + +How do we identify the tasks that were running when MCA/INIT was +delivered? + +If the previous task has been verified and converted to a blocked +state, then sos->prev_task on the MCA/INIT stack is updated to point to +the previous task. You can look at that field in dumps or debuggers. +To help distinguish between the handler and the original tasks, +handlers have _TIF_MCA_INIT set in thread_info.flags. + +The sos data is always in the MCA/INIT handler stack, at offset +MCA_SOS_OFFSET. You can get that value from mca_asm.h or calculate it +as KERNEL_STACK_SIZE - sizeof(struct pt_regs) - sizeof(struct +ia64_sal_os_state), with 16 byte alignment for all structures. + +Also the comm field of the MCA/INIT task is modified to include the pid +of the original task, for humans to use. For example, a comm field of +'MCA 12159' means that pid 12159 was running when the MCA was +delivered. diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 1f5f7d28c9e..5f08f9ce604 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -66,11 +66,11 @@ SETUP c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems). CONFIG_PROC_VMCORE=y d) Disable SMP support and build a UP kernel (Until it is fixed). - CONFIG_SMP=n + CONFIG_SMP=n e) Enable "Local APIC support on uniprocessors". - CONFIG_X86_UP_APIC=y + CONFIG_X86_UP_APIC=y f) Enable "IO-APIC support on uniprocessors" - CONFIG_X86_UP_IOAPIC=y + CONFIG_X86_UP_IOAPIC=y Note: i) Options a) and b) depend upon "Configure standard kernel features (for small systems)" (under General setup). @@ -95,6 +95,11 @@ SETUP hence have memory less than 4GB. iii) Specify "irqpoll" as command line parameter. This reduces driver initialization failures in second kernel due to shared interrupts. + iv) <root-dev> needs to be specified in a format corresponding to + the root device name in the output of mount command. + v) If you have built the drivers required to mount root file + system as modules in <second-kernel>, then, specify + --initrd=<initrd-for-second-kernel>. 5) System reboots into the second kernel when a panic occurs. A module can be written to force the panic or "ALT-SysRq-c" can be used initiate a crash diff --git a/Documentation/keys.txt b/Documentation/keys.txt index 0321ded4b9a..b22e7c8d059 100644 --- a/Documentation/keys.txt +++ b/Documentation/keys.txt @@ -195,8 +195,8 @@ KEY ACCESS PERMISSIONS ====================== Keys have an owner user ID, a group access ID, and a permissions mask. The mask -has up to eight bits each for user, group and other access. Only five of each -set of eight bits are defined. These permissions granted are: +has up to eight bits each for possessor, user, group and other access. Only +five of each set of eight bits are defined. These permissions granted are: (*) View @@ -241,16 +241,16 @@ about the status of the key service: type, description and permissions. The payload of the key is not available this way: - SERIAL FLAGS USAGE EXPY PERM UID GID TYPE DESCRIPTION: SUMMARY - 00000001 I----- 39 perm 1f0000 0 0 keyring _uid_ses.0: 1/4 - 00000002 I----- 2 perm 1f0000 0 0 keyring _uid.0: empty - 00000007 I----- 1 perm 1f0000 0 0 keyring _pid.1: empty - 0000018d I----- 1 perm 1f0000 0 0 keyring _pid.412: empty - 000004d2 I--Q-- 1 perm 1f0000 32 -1 keyring _uid.32: 1/4 - 000004d3 I--Q-- 3 perm 1f0000 32 -1 keyring _uid_ses.32: empty - 00000892 I--QU- 1 perm 1f0000 0 0 user metal:copper: 0 - 00000893 I--Q-N 1 35s 1f0000 0 0 user metal:silver: 0 - 00000894 I--Q-- 1 10h 1f0000 0 0 user metal:gold: 0 + SERIAL FLAGS USAGE EXPY PERM UID GID TYPE DESCRIPTION: SUMMARY + 00000001 I----- 39 perm 1f1f0000 0 0 keyring _uid_ses.0: 1/4 + 00000002 I----- 2 perm 1f1f0000 0 0 keyring _uid.0: empty + 00000007 I----- 1 perm 1f1f0000 0 0 keyring _pid.1: empty + 0000018d I----- 1 perm 1f1f0000 0 0 keyring _pid.412: empty + 000004d2 I--Q-- 1 perm 1f1f0000 32 -1 keyring _uid.32: 1/4 + 000004d3 I--Q-- 3 perm 1f1f0000 32 -1 keyring _uid_ses.32: empty + 00000892 I--QU- 1 perm 1f000000 0 0 user metal:copper: 0 + 00000893 I--Q-N 1 35s 1f1f0000 0 0 user metal:silver: 0 + 00000894 I--Q-- 1 10h 001f0000 0 0 user metal:gold: 0 The flags are: @@ -637,6 +637,34 @@ call, and the key released upon close. How to deal with conflicting keys due to two different users opening the same file is left to the filesystem author to solve. +Note that there are two different types of pointers to keys that may be +encountered: + + (*) struct key * + + This simply points to the key structure itself. Key structures will be at + least four-byte aligned. + + (*) key_ref_t + + This is equivalent to a struct key *, but the least significant bit is set + if the caller "possesses" the key. By "possession" it is meant that the + calling processes has a searchable link to the key from one of its + keyrings. There are three functions for dealing with these: + + key_ref_t make_key_ref(const struct key *key, + unsigned long possession); + + struct key *key_ref_to_ptr(const key_ref_t key_ref); + + unsigned long is_key_possessed(const key_ref_t key_ref); + + The first function constructs a key reference from a key pointer and + possession information (which must be 0 or 1 and not any other value). + + The second function retrieves the key pointer from a reference and the + third retrieves the possession flag. + When accessing a key's payload contents, certain precautions must be taken to prevent access vs modification races. See the section "Notes on accessing payload contents" for more information. @@ -665,7 +693,11 @@ payload contents" for more information. void key_put(struct key *key); - This can be called from interrupt context. If CONFIG_KEYS is not set then + Or: + + void key_ref_put(key_ref_t key_ref); + + These can be called from interrupt context. If CONFIG_KEYS is not set then the argument will not be parsed. @@ -689,13 +721,17 @@ payload contents" for more information. (*) If a keyring was found in the search, this can be further searched by: - struct key *keyring_search(struct key *keyring, - const struct key_type *type, - const char *description) + key_ref_t keyring_search(key_ref_t keyring_ref, + const struct key_type *type, + const char *description) This searches the keyring tree specified for a matching key. Error ENOKEY - is returned upon failure. If successful, the returned key will need to be - released. + is returned upon failure (use IS_ERR/PTR_ERR to determine). If successful, + the returned key will need to be released. + + The possession attribute from the keyring reference is used to control + access through the permissions mask and is propagated to the returned key + reference pointer if successful. (*) To check the validity of a key, this function can be called: @@ -732,7 +768,7 @@ More complex payload contents must be allocated and a pointer to them set in key->payload.data. One of the following ways must be selected to access the data: - (1) Unmodifyable key type. + (1) Unmodifiable key type. If the key type does not have a modify method, then the key's payload can be accessed without any form of locking, provided that it's known to be diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index ab65714d95f..b433c8a27e2 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -355,10 +355,14 @@ ip_dynaddr - BOOLEAN Default: 0 icmp_echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it. + Default: 0 + icmp_echo_ignore_broadcasts - BOOLEAN - If either is set to true, then the kernel will ignore either all - ICMP ECHO requests sent to it or just those to broadcast/multicast - addresses, respectively. + If set non-zero, then the kernel will ignore all ICMP ECHO and + TIMESTAMP requests sent to it via broadcast/multicast. + Default: 1 icmp_ratelimit - INTEGER Limit the maximal rates for sending ICMP packets whose type matches diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt index da711028e5f..66eaaab7773 100644 --- a/Documentation/oops-tracing.txt +++ b/Documentation/oops-tracing.txt @@ -205,8 +205,8 @@ Phone: 701-234-7556 Tainted kernels: Some oops reports contain the string 'Tainted: ' after the program -counter, this indicates that the kernel has been tainted by some -mechanism. The string is followed by a series of position sensitive +counter. This indicates that the kernel has been tainted by some +mechanism. The string is followed by a series of position-sensitive characters, each representing a particular tainted value. 1: 'G' if all modules loaded have a GPL or compatible license, 'P' if @@ -214,16 +214,25 @@ characters, each representing a particular tainted value. MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by insmod as GPL compatible are assumed to be proprietary. - 2: 'F' if any module was force loaded by insmod -f, ' ' if all + 2: 'F' if any module was force loaded by "insmod -f", ' ' if all modules were loaded normally. 3: 'S' if the oops occurred on an SMP kernel running on hardware that - hasn't been certified as safe to run multiprocessor. - Currently this occurs only on various Athlons that are not - SMP capable. + hasn't been certified as safe to run multiprocessor. + Currently this occurs only on various Athlons that are not + SMP capable. + + 4: 'R' if a module was force unloaded by "rmmod -f", ' ' if all + modules were unloaded normally. + + 5: 'M' if any processor has reported a Machine Check Exception, + ' ' if no Machine Check Exceptions have occurred. + + 6: 'B' if a page-release function has found a bad page reference or + some unexpected page flags. The primary reason for the 'Tainted: ' string is to tell kernel debuggers if this is a clean kernel or if anything unusual has -occurred. Tainting is permanent, even if an offending module is -unloading the tainted value remains to indicate that the kernel is not +occurred. Tainting is permanent: even if an offending module is +unloaded, the tainted value remains to indicate that the kernel is not trustworthy. diff --git a/Documentation/pm.txt b/Documentation/pm.txt index cc63ae18d14..2ea1149bf6b 100644 --- a/Documentation/pm.txt +++ b/Documentation/pm.txt @@ -38,6 +38,12 @@ system the associated daemon will exit gracefully. Driver Interface -- OBSOLETE, DO NOT USE! ----------------************************* + +Note: pm_register(), pm_access(), pm_dev_idle() and friends are +obsolete. Please do not use them. Instead you should properly hook +your driver into the driver model, and use its suspend()/resume() +callbacks to do this kind of stuff. + If you are writing a new driver or maintaining an old driver, it should include power management support. Without power management support, a single driver may prevent a system with power management diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index ebfcdf28485..13cba955cb5 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -75,7 +75,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. adsp_map - PCM device number maps assigned to the 2st OSS device. - Default: 1 nonblock_open - - Don't block opening busy PCM devices. + - Don't block opening busy PCM devices. Default: 1 For example, when dsp_map=2, /dev/dsp will be mapped to PCM #2 of the card #0. Similarly, when adsp_map=0, /dev/adsp will be mapped @@ -148,6 +148,16 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Module supports up to 8 cards. This module does not support autoprobe thus main port must be specified!!! Other ports are optional. + Module snd-ad1889 + ----------------- + + Module for Analog Devices AD1889 chips. + + ac97_quirk - AC'97 workaround for strange hardware + See the description of intel8x0 module for details. + + This module supports up to 8 cards. + Module snd-ali5451 ------------------ @@ -189,15 +199,20 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Module snd-atiixp ----------------- - Module for ATI IXP 150/200/250 AC97 controllers. + Module for ATI IXP 150/200/250/400 AC97 controllers. - ac97_clock - AC'97 clock (defalut = 48000) + ac97_clock - AC'97 clock (default = 48000) ac97_quirk - AC'97 workaround for strange hardware - See the description of intel8x0 module for details. + See "AC97 Quirk Option" section below. spdif_aclink - S/PDIF transfer over AC-link (default = 1) This module supports up to 8 cards and autoprobe. + ATI IXP has two different methods to control SPDIF output. One is + over AC-link and another is over the "direct" SPDIF output. The + implementation depends on the motherboard, and you'll need to + choose the correct one via spdif_aclink module option. + Module snd-atiixp-modem ----------------------- @@ -230,7 +245,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. The hardware EQ hardware and SPDIF is only present in the Vortex2 and Advantage. - Note: Some ALSA mixer applicactions don't handle the SPDIF samplerate + Note: Some ALSA mixer applications don't handle the SPDIF sample rate control correctly. If you have problems regarding this, try another ALSA compliant mixer (alsamixer works). @@ -302,7 +317,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. mpu_port - 0x300,0x310,0x320,0x330, 0 = disable (default) fm_port - 0x388 (default), 0 = disable (default) - soft_ac3 - Sofware-conversion of raw SPDIF packets (model 033 only) + soft_ac3 - Software-conversion of raw SPDIF packets (model 033 only) (default = 1) joystick_port - Joystick port address (0 = disable, 1 = auto-detect) @@ -384,7 +399,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Module for PCI sound cards based on CS4610/CS4612/CS4614/CS4615/CS4622/ CS4624/CS4630/CS4280 PCI chips. - external_amp - Force to enable external amplifer. + external_amp - Force to enable external amplifier. thinkpad - Force to enable Thinkpad's CLKRUN control. mmap_valid - Support OSS mmap mode (default = 0). @@ -620,7 +635,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. VIA VT8251/VT8237A model - force the model name - position_fix - Fix DMA pointer (0 = FIFO size, 1 = none, 2 = POSBUF) + position_fix - Fix DMA pointer (0 = auto, 1 = none, 2 = POSBUF, 3 = FIFO size) Module supports up to 8 cards. @@ -656,6 +671,11 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. allout 5-jack in back, 2-jack in front, SPDIF out auto auto-config reading BIOS (default) + If the default configuration doesn't work and one of the above + matches with your device, report it together with the PCI + subsystem ID (output of "lspci -nv") to ALSA BTS or alsa-devel + ML (see the section "Links and Addresses"). + Note 2: If you get click noises on output, try the module option position_fix=1 or 2. position_fix=1 will use the SD_LPIB register value without FIFO size correction as the current @@ -783,20 +803,13 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. ac97_clock - AC'97 codec clock base (0 = auto-detect) ac97_quirk - AC'97 workaround for strange hardware - The following strings are accepted: - default = don't override the default setting - disable = disable the quirk - hp_only = use headphone control as master - swap_hp = swap headphone and master controls - swap_surround = swap master and surround controls - ad_sharing = for AD1985, turn on OMS bit and use headphone - alc_jack = for ALC65x, turn on the jack sense mode - inv_eapd = inverted EAPD implementation - mute_led = bind EAPD bit for turning on/off mute LED - For backward compatibility, the corresponding integer - value -1, 0, ... are accepted, too. + See "AC97 Quirk Option" section below. buggy_irq - Enable workaround for buggy interrupts on some - motherboards (default off) + motherboards (default yes on nForce chips, + otherwise off) + buggy_semaphore - Enable workaround for hardwares with buggy + semaphores (e.g. on some ASUS laptops) + (default off) Module supports autoprobe and multiple bus-master chips (max 8). @@ -808,13 +821,6 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. motherboard has these devices, use the ns558 or snd-mpu401 modules, respectively. - The ac97_quirk option is used to enable/override the workaround - for specific devices. Some hardware have swapped output pins - between Master and Headphone, or Surround. The driver provides - the auto-detection of known problematic devices, but some might - be unknown or wrongly detected. In such a case, pass the proper - value with this option. - The power-management is supported. Module snd-intel8x0m @@ -966,7 +972,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. with machines with other (most likely CS423x or OPL3SAx) chips, even though the device is detected in lspci. In such a case, try other drivers, e.g. snd-cs4232 or snd-opl3sa2. Some has ISA-PnP - but some doesn't have ISA PnP. You'll need to speicfy isapnp=0 + but some doesn't have ISA PnP. You'll need to specify isapnp=0 and proper hardware parameters in the case without ISA PnP. Note: some laptops need a workaround for AC97 RESET. For the @@ -1302,7 +1308,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. channels [VIA8233/C, 8235, 8237 only] ac97_quirk - AC'97 workaround for strange hardware - See the description of intel8x0 module for details. + See "AC97 Quirk Option" section below. Module supports autoprobe and multiple bus-master chips (max 8). @@ -1327,16 +1333,17 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. "lspci -nv"). If dxs_support=5 does not work, try dxs_support=4; if it doesn't work too, try dxs_support=1. (dxs_support=1 is - usually for old motherboards. The correct implementated + usually for old motherboards. The correct implemented board should work with 4 or 5.) If it still doesn't work and the default setting is ok, dxs_support=3 is the right choice. If the default setting doesn't work at all, try dxs_support=2 to disable the DXS channels. In any cases, please let us know the result and the - subsystem vendor/device ids. + subsystem vendor/device ids. See "Links and Addresses" + below. Note: for the MPU401 on VIA823x, use snd-mpu401 driver - additonally. The mpu_port option is for VIA686 chips only. + additionally. The mpu_port option is for VIA686 chips only. Module snd-via82xx-modem ------------------------ @@ -1398,8 +1405,10 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Module supports up to 8 cards. The module is compiled only when PCMCIA is supported on kernel. - To activate the driver via the card manager, you'll need to set - up /etc/pcmcia/vxpocket.conf. See the sound/pcmcia/vx/vxpocket.c. + With the older 2.6.x kernel, to activate the driver via the card + manager, you'll need to set up /etc/pcmcia/vxpocket.conf. See the + sound/pcmcia/vx/vxpocket.c. 2.6.13 or later kernel requires no + longer require a config file. When the driver is compiled as a module and the hotplug firmware is supported, the firmware data is loaded via hotplug automatically. @@ -1411,6 +1420,9 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Note: the driver is build only when CONFIG_ISA is set. + Note2: snd-vxp440 driver is merged to snd-vxpocket driver since + ALSA 1.0.10. + Module snd-ymfpci ----------------- @@ -1436,6 +1448,37 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. Note: the driver is build only when CONFIG_ISA is set. +AC97 Quirk Option +================= + +The ac97_quirk option is used to enable/override the workaround for +specific devices on drivers for on-board AC'97 controllers like +snd-intel8x0. Some hardware have swapped output pins between Master +and Headphone, or Surround (thanks to confusion of AC'97 +specifications from version to version :-) + +The driver provides the auto-detection of known problematic devices, +but some might be unknown or wrongly detected. In such a case, pass +the proper value with this option. + +The following strings are accepted: + - default Don't override the default setting + - disable Disable the quirk + - hp_only Bind Master and Headphone controls as a single control + - swap_hp Swap headphone and master controls + - swap_surround Swap master and surround controls + - ad_sharing For AD1985, turn on OMS bit and use headphone + - alc_jack For ALC65x, turn on the jack sense mode + - inv_eapd Inverted EAPD implementation + - mute_led Bind EAPD bit for turning on/off mute LED + +For backward compatibility, the corresponding integer value -1, 0, +... are accepted, too. + +For example, if "Master" volume control has no effect on your device +but only "Headphone" does, pass ac97_quirk=hp_only module option. + + Configuring Non-ISAPNP Cards ============================ @@ -1553,6 +1596,8 @@ Proc interfaces (/proc/asound) - whole-frag write only whole fragments (optimization affecting playback only) - no-silence do not fill silence ahead to avoid clicks + - buggy-ptr Returns the whitespace blocks in GETOPTR ioctl + instead of filled blocks Example: echo "x11amp 128 16384" > /proc/asound/card0/pcm0p/oss echo "squake 0 0 disable" > /proc/asound/card0/pcm0c/oss @@ -1589,9 +1634,14 @@ commands to the snd-page-alloc driver: use. -Links -===== +Links and Addresses +=================== ALSA project homepage http://www.alsa-project.org + ALSA Bug Tracking System + https://bugtrack.alsa-project.org/bugs/ + + ALSA Developers ML + mailto:alsa-devel@lists.sourceforge.net diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl index 0475478c248..24e85520890 100644 --- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl @@ -447,7 +447,7 @@ .... /* allocate a chip-specific data with zero filled */ - chip = kcalloc(1, sizeof(*chip), GFP_KERNEL); + chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (chip == NULL) return -ENOMEM; @@ -949,7 +949,7 @@ After allocating a card instance via <function>snd_card_new()</function> (with <constant>NULL</constant> on the 4th arg), call - <function>kcalloc()</function>. + <function>kzalloc()</function>. <informalexample> <programlisting> @@ -958,7 +958,7 @@ mychip_t *chip; card = snd_card_new(index[dev], id[dev], THIS_MODULE, NULL); ..... - chip = kcalloc(1, sizeof(*chip), GFP_KERNEL); + chip = kzalloc(sizeof(*chip), GFP_KERNEL); ]]> </programlisting> </informalexample> @@ -1136,7 +1136,7 @@ return -ENXIO; } - chip = kcalloc(1, sizeof(*chip), GFP_KERNEL); + chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (chip == NULL) { pci_disable_device(pci); return -ENOMEM; @@ -1292,7 +1292,7 @@ need to initialize this number as -1 before actual allocation, since irq 0 is valid. The port address and its resource pointer can be initialized as null by - <function>kcalloc()</function> automatically, so you + <function>kzalloc()</function> automatically, so you don't have to take care of resetting them. </para> diff --git a/Documentation/sparse.txt b/Documentation/sparse.txt index 5df44dc894e..1829009db77 100644 --- a/Documentation/sparse.txt +++ b/Documentation/sparse.txt @@ -51,9 +51,9 @@ or you don't get any checking at all. Where to get sparse ~~~~~~~~~~~~~~~~~~~ -With BK, you can just get it from +With git, you can just get it from - bk://sparse.bkbits.net/sparse + rsync://rsync.kernel.org/pub/scm/devel/sparse/sparse.git and DaveJ has tar-balls at diff --git a/Documentation/usb/URB.txt b/Documentation/usb/URB.txt index d59b95cc6f1..a49e5f2c2b4 100644 --- a/Documentation/usb/URB.txt +++ b/Documentation/usb/URB.txt @@ -1,5 +1,6 @@ Revised: 2000-Dec-05. Again: 2002-Jul-06 +Again: 2005-Sep-19 NOTE: @@ -18,8 +19,8 @@ called USB Request Block, or URB for short. and deliver the data and status back. - Execution of an URB is inherently an asynchronous operation, i.e. the - usb_submit_urb(urb) call returns immediately after it has successfully queued - the requested action. + usb_submit_urb(urb) call returns immediately after it has successfully + queued the requested action. - Transfers for one URB can be canceled with usb_unlink_urb(urb) at any time. @@ -94,8 +95,9 @@ To free an URB, use void usb_free_urb(struct urb *urb) -You may not free an urb that you've submitted, but which hasn't yet been -returned to you in a completion callback. +You may free an urb that you've submitted, but which hasn't yet been +returned to you in a completion callback. It will automatically be +deallocated when it is no longer in use. 1.4. What has to be filled in? @@ -145,30 +147,36 @@ to get seamless ISO streaming. 1.6. How to cancel an already running URB? -For an URB which you've submitted, but which hasn't been returned to -your driver by the host controller, call +There are two ways to cancel an URB you've submitted but which hasn't +been returned to your driver yet. For an asynchronous cancel, call int usb_unlink_urb(struct urb *urb) It removes the urb from the internal list and frees all allocated -HW descriptors. The status is changed to reflect unlinking. After -usb_unlink_urb() returns with that status code, you can free the URB -with usb_free_urb(). +HW descriptors. The status is changed to reflect unlinking. Note +that the URB will not normally have finished when usb_unlink_urb() +returns; you must still wait for the completion handler to be called. -There is also an asynchronous unlink mode. To use this, set the -the URB_ASYNC_UNLINK flag in urb->transfer flags before calling -usb_unlink_urb(). When using async unlinking, the URB will not -normally be unlinked when usb_unlink_urb() returns. Instead, wait -for the completion handler to be called. +To cancel an URB synchronously, call + + void usb_kill_urb(struct urb *urb) + +It does everything usb_unlink_urb does, and in addition it waits +until after the URB has been returned and the completion handler +has finished. It also marks the URB as temporarily unusable, so +that if the completion handler or anyone else tries to resubmit it +they will get a -EPERM error. Thus you can be sure that when +usb_kill_urb() returns, the URB is totally idle. 1.7. What about the completion handler? The handler is of the following type: - typedef void (*usb_complete_t)(struct urb *); + typedef void (*usb_complete_t)(struct urb *, struct pt_regs *) -i.e. it gets just the URB that caused the completion call. +I.e., it gets the URB that caused the completion call, plus the +register values at the time of the corresponding interrupt (if any). In the completion handler, you should have a look at urb->status to detect any USB errors. Since the context parameter is included in the URB, you can pass information to the completion handler. @@ -176,17 +184,11 @@ you can pass information to the completion handler. Note that even when an error (or unlink) is reported, data may have been transferred. That's because USB transfers are packetized; it might take sixteen packets to transfer your 1KByte buffer, and ten of them might -have transferred succesfully before the completion is called. +have transferred succesfully before the completion was called. NOTE: ***** WARNING ***** -Don't use urb->dev field in your completion handler; it's cleared -as part of giving urbs back to drivers. (Addressing an issue with -ownership of periodic URBs, which was otherwise ambiguous.) Instead, -use urb->context to hold all the data your driver needs. - -NOTE: ***** WARNING ***** -Also, NEVER SLEEP IN A COMPLETION HANDLER. These are normally called +NEVER SLEEP IN A COMPLETION HANDLER. These are normally called during hardware interrupt processing. If you can, defer substantial work to a tasklet (bottom half) to keep system latencies low. You'll probably need to use spinlocks to protect data structures you manipulate @@ -229,24 +231,10 @@ ISO data with some other event stream. Interrupt transfers, like isochronous transfers, are periodic, and happen in intervals that are powers of two (1, 2, 4 etc) units. Units are frames for full and low speed devices, and microframes for high speed ones. - -Currently, after you submit one interrupt URB, that urb is owned by the -host controller driver until you cancel it with usb_unlink_urb(). You -may unlink interrupt urbs in their completion handlers, if you need to. - -After a transfer completion is called, the URB is automagically resubmitted. -THIS BEHAVIOR IS EXPECTED TO BE REMOVED!! - -Interrupt transfers may only send (or receive) the "maxpacket" value for -the given interrupt endpoint; if you need more data, you will need to -copy that data out of (or into) another buffer. Similarly, you can't -queue interrupt transfers. -THESE RESTRICTIONS ARE EXPECTED TO BE REMOVED!! - -Note that this automagic resubmission model does make it awkward to use -interrupt OUT transfers. The portable solution involves unlinking those -OUT urbs after the data is transferred, and perhaps submitting a final -URB for a short packet. - The usb_submit_urb() call modifies urb->interval to the implemented interval value that is less than or equal to the requested interval value. + +In Linux 2.6, unlike earlier versions, interrupt URBs are not automagically +restarted when they complete. They end when the completion handler is +called, just like other URBs. If you want an interrupt URB to be restarted, +your completion handler must resubmit it. |