The following is a list of files and features that are going to be removed in the kernel source tree. Every entry should contain what exactly is going away, why it is happening, and who is going to be doing the work. When the feature is removed from the kernel, it should also be removed from this file. --------------------------- What: dev->power.power_state When: July 2007 Why: Broken design for runtime control over driver power states, confusing driver-internal runtime power management with: mechanisms to support system-wide sleep state transitions; event codes that distinguish different phases of swsusp "sleep" transitions; and userspace policy inputs. This framework was never widely used, and most attempts to use it were broken. Drivers should instead be exposing domain-specific interfaces either to kernel or to userspace. Who: Pavel Machek --------------------------- What: old NCR53C9x driver When: October 2007 Why: Replaced by the much better esp_scsi driver. Actual low-level driver can be ported over almost trivially. Who: David Miller Christoph Hellwig --------------------------- What: Video4Linux API 1 ioctls and video_decoder.h from Video devices. When: December 2008 Files: include/linux/video_decoder.h include/linux/videodev.h Check: include/linux/video_decoder.h include/linux/videodev.h Why: V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6 series. The old API have lots of drawbacks and don't provide enough means to work with all video and audio standards. The newer API is already available on the main drivers and should be used instead. Newer drivers should use v4l_compat_translate_ioctl function to handle old calls, replacing to newer ones. Decoder iocts are using internally to allow video drivers to communicate with video decoders. This should also be improved to allow V4L2 calls being translated into compatible internal ioctls. Compatibility ioctls will be provided, for a while, via v4l1-compat module. Who: Mauro Carvalho Chehab --------------------------- What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl]) When: November 2005 Files: drivers/pcmcia/: pcmcia_ioctl.c Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a normal hotpluggable bus, and with it using the default kernel infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA control ioctl needed by cardmgr and cardctl from pcmcia-cs is unnecessary, and makes further cleanups and integration of the PCMCIA subsystem into the Linux kernel device driver model more difficult. The features provided by cardmgr and cardctl are either handled by the kernel itself now or are available in the new pcmciautils package available at http://kernel.org/pub/linux/utils/kernel/pcmcia/ Who: Dominik Brodowski --------------------------- What: sys_sysctl When: September 2010 Option: CONFIG_SYSCTL_SYSCALL Why: The same information is available in a more convenient from /proc/sys, and none of the sysctl variables appear to be important performance wise. Binary sysctls are a long standing source of subtle kernel bugs and security issues. When I looked several months ago all I could find after searching several distributions were 5 user space programs and glibc (which falls back to /proc/sys) using this syscall. The man page for sysctl(2) documents it as unusable for user space programs. sysctl(2) is not generally ABI compatible to a 32bit user space application on a 64bit and a 32bit kernel. For the last several months the policy has been no new binary sysctls and no one has put forward an argument to use them. Binary sysctls issues seem to keep happening appearing so properly deprecating them (with a warning to user space) and a 2 year grace warning period will mean eventually we can kill them and end the pain. In the mean time individual binary sysctls can be dealt with in a piecewise fashion. Who: Eric Biederman --------------------------- What: remove EXPORT_SYMBOL(kernel_thread) When: August 2006 Files: arch/*/kernel/*_ksyms.c Check: kernel_thread Why: kernel_thread is a low-level implementation detail. Drivers should use the API instead which shields them from implementation details and provides a higherlevel interface that prevents bugs and code duplication Who: Christoph Hellwig --------------------------- What: eepro100 network driver When: January 2007 Why: replaced by the e100 driver Who: Adrian Bunk --------------------------- What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports (temporary transition config option provided until then) The transition config option will also be removed at the same time. When: before 2.6.19 Why: Unused symbols are both increasing the size of the kernel binary and are often a sign of "wrong API" Who: Arjan van de Ven --------------------------- What: vm_ops.nopage When: Soon, provided in-kernel callers have been converted Why: This interface is replaced by vm_ops.fault, but it has been around forever, is used by a lot of drivers, and doesn't cost much to maintain. Who: Nick Piggin --------------------------- What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment When: October 2008 Why: The stacking of class devices makes these values misleading and inconsistent. Class devices should not carry any of these properties, and bus devices have SUBSYTEM and DRIVER as a replacement. Who: Kay Sievers --------------------------- What: ACPI procfs interface When: July 2008 Why: ACPI sysfs conversion should be finished by January 2008. ACPI procfs interface will be removed in July 2008 so that there is enough time for the user space to catch up. Who: Zhang Rui --------------------------- What: /proc/acpi/button When: August 2007 Why: /proc/acpi/button has been replaced by events to the input layer since 2.6.20. Who: Len Brown --------------------------- What: /proc/acpi/event When: February 2008 Why: /proc/acpi/event has been replaced by events via the input layer and netlink since 2.6.23. Who: Len Brown --------------------------- What: libata spindown skipping and warning When: Dec 2008 Why: Some halt(8) implementations synchronize caches for and spin down libata disks because libata didn't use to spin down disk on system halt (only synchronized caches). Spin down on system halt is now implemented. sysfs node /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if spin down support is available. Because issuing spin down command to an already spun down disk makes some disks spin up just to spin down again, libata tracks device spindown status to skip the extra spindown command and warn about it. This is to give userspace tools the time to get updated and will be removed after userspace is reasonably updated. Who: Tejun Heo --------------------------- What: The arch/ppc and include/asm-ppc directories When: Jun 2008 Why: The arch/powerpc tree is the merged architecture for ppc32 and ppc64 platforms. Currently there are efforts underway to port the remaining arch/ppc platforms to the merged tree. New submissions to the arch/ppc tree have been frozen with the 2.6.22 kernel release and that tree will remain in bug-fix only mode until its scheduled removal. Platforms that are not ported by June 2008 will be removed due to the lack of an interested maintainer. Who: linuxppc-dev@ozlabs.org --------------------------- What: i386/x86_64 bzImage symlinks When: April 2010 Why: The i386/x86_64 merge provides a symlink to the old bzImage location so not yet updated user space tools, e.g. package scripts, do not break. Who: Thomas Gleixner --------------------------- What: i2c-i810, i2c-prosavage and i2c-savage4 When: May 2008 Why: These drivers are superseded by i810fb, intelfb and savagefb. Who: Jean Delvare --------------------------- What (Why): - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files (superseded by xt_TOS/xt_tos target & match) - "forwarding" header files like ipt_mac.h in include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/ - xt_CONNMARK match revision 0 (superseded by xt_CONNMARK match revision 1) - xt_MARK target revisions 0 and 1 (superseded by xt_MARK match revision 2) - xt_connmark match revision 0 (superseded by xt_connmark match revision 1) - xt_conntrack match revision 0 (superseded by xt_conntrack match revision 1) - xt_iprange match revision 0, include/linux/netfilter_ipv4/ipt_iprange.h (superseded by xt_iprange match revision 1) - xt_mark match revision 0 (superseded by xt_mark match revision 1) When: January 2009 or Linux 2.7.0, whichever comes first Why: Superseded by newer revisions or modules Who: Jan Engelhardt --------------------------- What: b43 support for firmware revision < 410 When: July 2008 Why: The support code for the old firmware hurts code readability/maintainability and slightly hurts runtime performance. Bugfixes for the old firmware are not provided by Broadcom anymore. Who: Michael Buesch --------------------------- What: Solaris/SunOS syscall and binary support on Sparc When: 2.6.26 Why: Largely unmaintained and almost entirely unused. File system layering used to divert library and dynamic linker searches to /usr/gnemul is extremely buggy and unfixable. Making it work is largely pointless as without a lot of work only the most trivial of Solaris binaries can work with the emulation code. Who: David S. Miller --------------------------- What: init_mm export When: 2.6.26 Why: Not used in-tree. The current out-of-tree users used it to work around problems in the CPA code which should be resolved by now. One usecase was described to provide verification code of the CPA operation. That's a good idea in general, but such code / infrastructure should be in the kernel and not in some out-of-tree driver. Who: Thomas Gleixner ---------------------------- What: usedac i386 kernel parameter When: 2.6.27 Why: replaced by allowdac and no dac combination Who: Glauber Costa --------------------------- What: /sys/o2cb symlink When: January 2010 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb exists as a symlink for backwards compatibility for old versions of ocfs2-tools. 2 years should be sufficient time to phase in new versions which know to look in /sys/fs/o2cb. Who: ocfs2-devel@oss.oracle.com --------------------------- What: asm/semaphore.h When: 2.6.26 Why: Implementation became generic; users should now include linux/semaphore.h instead. Who: Matthew Wilcox