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2006-12-07video1394: small optimizations to frame retrieval codepathDaniel Drake
Add some GCC branch prediction optimizations to unlikely error/safety conditions in the ioctl handling code commonly called during an application's capture loop. Signed-off-by: Daniel Drake <ddrake@brontes3d.com> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: handle sysfs errorsStefan Richter
Handle driver core errors with as much care as appropriate. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: coding style in hosts.cStefan Richter
Some 80-columns pedantry, and touch up of a // comment. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: lock smaller region by host_num_alloc mutexStefan Richter
We need the mutex only around the iteration over existing hosts. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: usecs_to_jiffies takes unsigned int argumentStefan Richter
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: ohci1394: suspend/resume cosmeticsStefan Richter
Reorder the definitions of ohci1394_pci_suspend and _resume. Remove redundant comments. Beautify return statements. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ohci1394: steps to implement suspend/resumeBernhard Kaindl
I did a quick shot on what I described and the appended patch does the first thing needed for working suspend/resume in ohci1394 which is HW de- and re-initialisation. It works with suspend2disk on my Ricoh R5C552 IEEE 1394 Controller with the 2.6.17 kernel to the extent that if I call dvgrab --interactive after suspend2disk without unloading ohci1394, it does not lock up dvgrab with 100% CPU but properly connects to the camera, given that I first unplug and plug the camera after coming back from suspend. I guess that could be fixed by forcing a bus reset in the resume function. I cannot test suspend to RAM here at the moment and should follow the guidelines in Documentation/power/pci.txt also, so this is rather a quick report than a finished patch and there are some rough edges: However, with this patch, I have to unload at least some in-kernel users of ohci1394 like dv1394 or video1394 before suspending. Not doing that caused an Oops and a bad tasklet error, probably from not handling ISO tasklets during suspend/resume properly. Maybe these can be temporarily cleared or unregistered and re-registered for suspend/resume with help from the other layers or from the highlevel 1394 core, but I do not really know what these do. But this patch provides a useful base to start from and is already of much help for people which do not need dv1394 and video1394 or can unload them at least during suspend. I cannot test function with sbp2 at the moment, but raw1394 seems to work fine. Signed-off-by: Bernhard Kaindl <bk@fsfe.org> Update 1: merge with previous two ohci1394 suspend/resume patches Update 2: version for application on top of Linux 2.6.19-rc4 Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: raw1394: add comments on lock usageStefan Richter
Add a who-is-who about some locks and list heads in raw1394's struct definitions. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: sbp2: slightly reorder sbp2scsi_abortStefan Richter
Put the target's fetch agent into reset state before the underlying ORB DMA is unmapped and the ->done handler is called. It is highly unlikely but the target could access that ORB right before sbp2 sends the reset request. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07ieee1394: remove unused struct member from highlevel APIStefan Richter
struct hpsb_highlevel's struct module *owner is neither used by the IEEE 1394 core nor set by any of the in-tree drivers or the two out-of-tree highlevel drivers I know about (dfg1394, mem1394) --- nor is this member documented. An unscheduled removal seems acceptable. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07[PATCH] Add include/linux/freezer.h and move definitions from sched.hNigel Cunningham
Move process freezing functions from include/linux/sched.h to freezer.h, so that modifications to the freezer or the kernel configuration don't require recompiling just about everything. [akpm@osdl.org: fix ueagle driver] Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove kmem_cache_tChristoph Lameter
Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_KERNELChristoph Lameter
SLAB_KERNEL is an alias of GFP_KERNEL. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_ATOMICChristoph Lameter
SLAB_ATOMIC is an alias of GFP_ATOMIC Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-22WorkStruct: make allyesconfigDavid Howells
Fix up for make allyesconfig. Signed-Off-By: David Howells <dhowells@redhat.com>
2006-10-30[ETH1394]: Fix unaligned accesses.David S. Miller
Several u64 objects are derefernced in situations where the pointer is not guarenteed to be aligned correctly. Use get_unaligned() as needed. Thanks to Will Simoneau for lots of testing and debugging help. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-10-29ieee1394: ohci1394: revert fail on error in suspendStefan Richter
Some errors during preparation for suspended state can be skipped with a warning instead of a failure of the whole suspend transition, notably an error in pci_set_power_state. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-10-08Merge branch 'upstream-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: ieee1394: nodemgr: fix startup of knodemgrd
2006-10-08ieee1394: nodemgr: fix startup of knodemgrdStefan Richter
Revert a thinko in commit d2f119fe319528da8c76a1107459d6f478cbf28c: When knodemgrd starts, it needs to sleep until host->generation was incremented above its initial value of 0. My wrong logic caused it to start sending requests when the bus wasn't completely ready. Seen as "AT dma reset ctx=0, aborting transmission" messages in 2.6.19-rc1. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-10-05IRQ: Maintain regs pointer globally rather than passing to IRQ handlersDavid Howells
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-03Fix several typos in drivers/Matt LaPlante
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-09-30Merge branch 'upstream-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (48 commits) ieee1394: raw1394: arm functions slept in atomic context ieee1394: sbp2: enable auto spin-up for all SBP-2 devices MAINTAINERS: updates to IEEE 1394 subsystem maintainership ieee1394: ohci1394: check for errors in suspend or resume set power state of firewire host during suspend ieee1394: ohci1394: more obvious endianess handling ieee1394: ohci1394: fix endianess bug in debug message ieee1394: sbp2: don't prefer MODE SENSE 10 ieee1394: nodemgr: grab class.subsys.rwsem in nodemgr_resume_ne ieee1394: nodemgr: fix rwsem recursion ieee1394: sbp2: more help in Kconfig ieee1394: sbp2: prevent rare deadlock in shutdown ieee1394: sbp2: update includes ieee1394: sbp2: better handling of transport errors ieee1394: sbp2: recheck node generation in sbp2_update ieee1394: sbp2: safer agent reset in error handlers ieee1394: sbp2: handle "sbp2util_node_write_no_wait failed" CONFIG_PM=n slim: drivers/ieee1394/ohci1394.c ieee1394: safer definition of empty macros video1394: add poll file operation support ...
2006-09-26i2c-algo-bit: Discard the mdelay data struct memberJean Delvare
i2c-algo-bit: Discard the mdelay data struct member The i2c_algo_bit_data structure has an mdelay member, which is not used by the algorithm code (the code has always been ifdef'd out.) Let's discard it to save some code and memory. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br> Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-23ieee1394: raw1394: arm functions slept in atomic contextStefan Richter
Sleeping functions like copy_to_user were accessed inside spinlocks in raw1394's arm_register, arm_unregister, arm_get_buf, arm_set_buf. http://bugzilla.kernel.org/show_bug.cgi?id=7120 Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Tested-by: David Trent <DTrent@piacton.com> (cherry picked from e575953ec17c3f5c1e738847d2d16c241bb99783 commit)
2006-09-17ieee1394: sbp2: enable auto spin-up for all SBP-2 devicesStefan Richter
This is a follow-up to patch "ieee1394: sbp2: enable auto spin-up for Maxtor disks". When I 'ejected' an OXUF922 based HDD from a Mac OS X box, it was spun down by the Mac and did not spin up by itself when attached to a Linux box right after that. The first SCSI command that required the bridge to access the drive ended in sda:<6>sd 18:0:0:0: Device not ready: <6>: Current: sense key: Not Ready Additional sense: Logical unit not ready, initializing cmd. required Therefore the flag which instructs scsi_mod to send START STOP UNIT with START=1 ("make medium ready") after such a condition is now enabled unconditionally for all FireWire storage devices. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: ohci1394: check for errors in suspend or resumeStefan Richter
Some of the suspend and resume litany may fail. Tell the PCI core about it. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17set power state of firewire host during suspendPavel Machek
Put firewire host controller in PCI Dx state for system suspend. (I was not able to measure any power savings, but it sounds like right thing to do, anyway.) Signed-off-by: Pavel Machek <pavel@suse.cz> Update by stefanr: Shuffle with existing PPC_PMAC code. Set power state in the resume hook too. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: ohci1394: more obvious endianess handlingStefan Richter
Rename ohci1394's packet_swab to header_le32_to_cpu to better reflect what it actually does. Also, define a constant array as 'const' and check the array index properly. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: ohci1394: fix endianess bug in debug messageStefan Richter
The transaction labels were misprinted int the debug printk "Packet received from node..." due two byte-swapping once too often. Affected were big endian machines, except UniNorth based ones. Fix tested by Wolfgang Pfeiffer. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: don't prefer MODE SENSE 10Stefan Richter
In the old days, sbp2 used to coerce all MODE SENSE commands into the 10 bytes version. When all command set conversions were removed from sbp2 several months ago, sdev->use_10_for_ms = 1 was added. Meaning, higher SCSI layers preferred the 10 bytes version but would try the 6 bytes version if the former failed. Recently, a problem with the 10 bytes version was discovered. An Initio INIC-1530 firmware accepted the 10 bytes version but replied with bogus data, showing the HDD incorrectly as write-protected. Since RBC actually mandates MODE SENSE (6), I checked which version was sent by Windows XP and Mac OS X 10.3 to an SBP-2 target hosted by Linux --- it was the 6 bytes version. (Exception: OS X sent the 10 bytes version to an MMC target. RBC and SBC got MODE SENSE (6).) Therefore, drop the use_10_for_ms flag from sbp2. Now the upper layers will try MODE SENSE (6) before MODE SENSE (10) on all SBP-2 devices. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: nodemgr: grab class.subsys.rwsem in nodemgr_resume_neStefan Richter
nodemgr_resume_ne was iterating over nodemgr_ud_class.children without protection by nodemgr_ud_class.subsys.rwsem. FIXME: Shouldn't we rather use class->sem there, not class->subsys.rwsem? Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: nodemgr: fix rwsem recursionStefan Richter
nodemgr_update_pdrv grabbed an rw semaphore (as reader) which was already taken by its caller's caller, nodemgr_probe_ne (as reader too). Reported by Miles Lane, call path pointed out by Arjan van de Ven. FIXME: Shouldn't we rather use class->sem there, not class->subsys.rwsem? Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: more help in KconfigStefan Richter
Add some pointers to SCSI to the configuration menu item of sbp2. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: prevent rare deadlock in shutdownStefan Richter
Scsi_remove_device() may go into uninterruptible sleep if blocked. Therefore sbp2_remove() unblocks the Scsi_Host before the device is requested to be removed. But there could be another 1394 bus reset after that which would block the host again. The 1394 subsystem won't call sbp2_update() concurrently to sbp2_remove(), which is why there is no chance for sbp2_remove() to be unblocked by sbp2_update(). The fix is to tell sbp2's bus reset handler when a device is to be shut down so that it skips scsi_block_requests() on that host. As before, any new commands after a reset without reconnect will be failed quickly by sbp2scsi_queuecommand(). In the long term, means to go without scsi_block_requests() should be found. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: update includesStefan Richter
Remove unused includes. Add missing includes, i.e. explicitly include all used headers. Sort includes alphabetically. Replace one call to signal_pending(current) to avoid to include headers just for this line. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: better handling of transport errorsStefan Richter
If the target signals a transport failure via status block, complete the request with DID_BUSY to indicate to the SCSI subsystem that the command may succeed when retried. Also log diagnostic information if the status block shows a transport related problem. It may point to hardware faults. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: recheck node generation in sbp2_updateStefan Richter
While sbp2_update() is doing its duties after a bus reset, another reset could happen. Don't accept new requests until the next undisturbed sbp2_update() or until sbp2_remove(). Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: safer agent reset in error handlersStefan Richter
The scsi_host_template's eh_abort_handler and eh_device_reset_handler are allowed to sleep. Use this to run sbp2_agent_reset in the more reliable mode which returns _after_ its write transaction was finished. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: handle "sbp2util_node_write_no_wait failed"Stefan Richter
Fix for http://bugzilla.kernel.org/show_bug.cgi?id=6948 Because sbp2 writes to the target's fetch agent's registers from within atomic context, it cannot sleep to guaranteedly get a free transaction label. This may repeatedly lead to "sbp2util_node_write_no_wait failed" and consequently to SCSI command abortion after timeout. A likely cause is that many queue_command softirqs may occur before khpsbpkt (the ieee1394 driver's thread which cleans up after finished transactions) is woken up to recycle tlabels. Sbp2 now schedules a workqueue job whenever sbp2_link_orb_command fails in sbp2util_node_write_no_wait. The job will reliably get a transaction label because it can sleep. We use the kernel-wide shared workqueue because it is unlikely that the job itself actually needs to sleep. In the improbable case that it has to sleep, it doesn't need to sleep long since the standard transaction timeout is 100ms. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17CONFIG_PM=n slim: drivers/ieee1394/ohci1394.cAlexey Dobriyan
Remove some code which is unneeded if CONFIG_PM=n. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: safer definition of empty macrosStefan Richter
A deactivated macro, defined as "#define foo(bar)", will result in silent corruption if somebody forgets a semicolon after a call to foo. Replace it by "#define foo(bar) do {} while (0)" which will reveal any respective syntax errors. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17video1394: add poll file operation supportDavid Moore
This patch adds support for the poll file operation to the video1394 driver. Signed-off-by: David Moore <dcm@acm.org> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17the scheduled removal of drivers/ieee1394/sbp2.c:force_inquiry_hackAdrian Bunk
This patch contains the scheduled removal of the force_inquiry_hack module parameter. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17Initialize ieee1394 early when built inAndi Kleen
This makes debugging with firescope easier. Signed-off-by: Andi Kleen <ak@suse.de> (original patch) Update: - no need for #ifdef MODULE - add comment in ieee1394_core, more verbose comment in ohci1394 Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (update)
2006-09-17ieee1394: sbp2: convert sbp2util_down_timeout to waitqueueStefan Richter
The waitqueue API is used to replace a custom wait mechanism. Only one global waitqueue (instead of per-device waitqueues or completions) is added because there is usually just one waiter. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: more checks of status blockStefan Richter
- Add checks for the (very unlikely) cases that the target writes too little or too much status data or writes unsolicited status. - Indicate that these and similar conditions are unlikely(). - Check the 'resp' and 'sbp_status' fields for possible failure status. - Slightly optimize access macros for the status block bitfields. - Unify a few related log messages. TODO: Check if 'src'==1, then withhold the respective ORB from reuse until status for any subsequent ORB was received. This is an old bug whose fix requires more complex command queue handling. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: safer initialization of status fifoStefan Richter
Sbp2's copy of the status fifo was cleared when management ORBs or new command ORBs were prepared. The latter had potential for a race condition if the block layer's soft IRQ and the 1394 LLD's interrupt handler ran on different CPUs. It would also yield wrong status if a command was completed with non-zero completion status before other commands that had zero completion status, and no new command was enqueued in the meantime. Now, the status buffer is cleared right before it is written. Thus it ends up in the following simpler and safer access pattern: - sbp2_alloc_device: allocates and implicitly clears once, - sbp2_handle_status_write: clears, writes, and reads, - sbp2_query_logins, sbp2_login_device, sbp2_reconnect_device: read. The latter three do not race with sbp2_handle_status_write because of how the protocol works. As a tiny optimization, the first two quadlets of the status never need to be cleared. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: optimize DMA direction of command ORBsStefan Richter
Only the driver writes ORBs, the device just reads them. Therefore PCI_DMA_BIDIRECTIONAL can be replaced by PCI_DMA_TODEVICE which may be cheaper on some architectures. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: discard return value of sbp2_link_orb_commandStefan Richter
Since sbp2 is at the moment unable to do anything with the return value of sbp2_link_orb_command, just discard it. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17ieee1394: sbp2: safer last_orb and next_ORB handlingStefan Richter
The sbp2 initiator has two ways to tell a target's fetch agent about new command ORBs: - Write the ORB's address to the ORB_POINTER register. This must not be done while the fetch agent is active. - Put the ORB's address into the previously submitted ORB's next_ORB field and write to the DOORBELL register. This may be done while the fetch agent is active or suspended. It must not be done while the fetch agent is in reset state. Sbp2 has a last_orb pointer which indicates in what way a new command should be announced. That pointer is concurrently accessed at various occasions. Furthermore, initiator and target are accessing the next_ORB field of ORBs concurrently and asynchronously. This patch does: - Protect all initiator accesses to last_orb by sbp2_command_orb_lock. - Add pci_dma_sync_single_for_device before a previously submitted ORB's next_ORB field is overwritten. - Insert a memory barrier between when next_ORB_lo and next_ORB_hi are overwritten. Next_ORB_hi must not be updated before next_ORB_lo. - Remove the rather unspecific and now superfluous qualifier "volatile" from the next_ORB fields. - Add comments on how last_orb is connected with what is known about the target's fetch agent's state. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>