feature-removal-schedule.txt 12 KB

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  1. The following is a list of files and features that are going to be
  2. removed in the kernel source tree. Every entry should contain what
  3. exactly is going away, why it is happening, and who is going to be doing
  4. the work. When the feature is removed from the kernel, it should also
  5. be removed from this file.
  6. ---------------------------
  7. What: /sys/devices/.../power/state
  8. dev->power.power_state
  9. dpm_runtime_{suspend,resume)()
  10. When: July 2007
  11. Why: Broken design for runtime control over driver power states, confusing
  12. driver-internal runtime power management with: mechanisms to support
  13. system-wide sleep state transitions; event codes that distinguish
  14. different phases of swsusp "sleep" transitions; and userspace policy
  15. inputs. This framework was never widely used, and most attempts to
  16. use it were broken. Drivers should instead be exposing domain-specific
  17. interfaces either to kernel or to userspace.
  18. Who: Pavel Machek <pavel@suse.cz>
  19. ---------------------------
  20. What: RAW driver (CONFIG_RAW_DRIVER)
  21. When: December 2005
  22. Why: declared obsolete since kernel 2.6.3
  23. O_DIRECT can be used instead
  24. Who: Adrian Bunk <bunk@stusta.de>
  25. ---------------------------
  26. What: drivers that were depending on OBSOLETE_OSS_DRIVER
  27. (config options already removed)
  28. When: before 2.6.19
  29. Why: OSS drivers with ALSA replacements
  30. Who: Adrian Bunk <bunk@stusta.de>
  31. ---------------------------
  32. What: raw1394: requests of type RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN
  33. When: November 2006
  34. Why: Deprecated in favour of the new ioctl-based rawiso interface, which is
  35. more efficient. You should really be using libraw1394 for raw1394
  36. access anyway.
  37. Who: Jody McIntyre <scjody@modernduck.com>
  38. ---------------------------
  39. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  40. When: December 2006
  41. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  42. series. The old API have lots of drawbacks and don't provide enough
  43. means to work with all video and audio standards. The newer API is
  44. already available on the main drivers and should be used instead.
  45. Newer drivers should use v4l_compat_translate_ioctl function to handle
  46. old calls, replacing to newer ones.
  47. Decoder iocts are using internally to allow video drivers to
  48. communicate with video decoders. This should also be improved to allow
  49. V4L2 calls being translated into compatible internal ioctls.
  50. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  51. ---------------------------
  52. What: sys_sysctl
  53. When: January 2007
  54. Why: The same information is available through /proc/sys and that is the
  55. interface user space prefers to use. And there do not appear to be
  56. any existing user in user space of sys_sysctl. The additional
  57. maintenance overhead of keeping a set of binary names gets
  58. in the way of doing a good job of maintaining this interface.
  59. Who: Eric Biederman <ebiederm@xmission.com>
  60. ---------------------------
  61. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  62. When: November 2005
  63. Files: drivers/pcmcia/: pcmcia_ioctl.c
  64. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  65. normal hotpluggable bus, and with it using the default kernel
  66. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  67. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  68. unnecessary, and makes further cleanups and integration of the
  69. PCMCIA subsystem into the Linux kernel device driver model more
  70. difficult. The features provided by cardmgr and cardctl are either
  71. handled by the kernel itself now or are available in the new
  72. pcmciautils package available at
  73. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  74. Who: Dominik Brodowski <linux@brodo.de>
  75. ---------------------------
  76. What: ip_queue and ip6_queue (old ipv4-only and ipv6-only netfilter queue)
  77. When: December 2005
  78. Why: This interface has been obsoleted by the new layer3-independent
  79. "nfnetlink_queue". The Kernel interface is compatible, so the old
  80. ip[6]tables "QUEUE" targets still work and will transparently handle
  81. all packets into nfnetlink queue number 0. Userspace users will have
  82. to link against API-compatible library on top of libnfnetlink_queue
  83. instead of the current 'libipq'.
  84. Who: Harald Welte <laforge@netfilter.org>
  85. ---------------------------
  86. What: remove EXPORT_SYMBOL(kernel_thread)
  87. When: August 2006
  88. Files: arch/*/kernel/*_ksyms.c
  89. Why: kernel_thread is a low-level implementation detail. Drivers should
  90. use the <linux/kthread.h> API instead which shields them from
  91. implementation details and provides a higherlevel interface that
  92. prevents bugs and code duplication
  93. Who: Christoph Hellwig <hch@lst.de>
  94. ---------------------------
  95. What: CONFIG_FORCED_INLINING
  96. When: June 2006
  97. Why: Config option is there to see if gcc is good enough. (in january
  98. 2006). If it is, the behavior should just be the default. If it's not,
  99. the option should just go away entirely.
  100. Who: Arjan van de Ven
  101. ---------------------------
  102. What: START_ARRAY ioctl for md
  103. When: July 2006
  104. Files: drivers/md/md.c
  105. Why: Not reliable by design - can fail when most needed.
  106. Alternatives exist
  107. Who: NeilBrown <neilb@suse.de>
  108. ---------------------------
  109. What: eepro100 network driver
  110. When: January 2007
  111. Why: replaced by the e100 driver
  112. Who: Adrian Bunk <bunk@stusta.de>
  113. ---------------------------
  114. What: drivers depending on OSS_OBSOLETE_DRIVER
  115. When: options in 2.6.20, code in 2.6.22
  116. Why: OSS drivers with ALSA replacements
  117. Who: Adrian Bunk <bunk@stusta.de>
  118. ---------------------------
  119. What: pci_module_init(driver)
  120. When: January 2007
  121. Why: Is replaced by pci_register_driver(pci_driver).
  122. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  123. ---------------------------
  124. What: Usage of invalid timevals in setitimer
  125. When: March 2007
  126. Why: POSIX requires to validate timevals in the setitimer call. This
  127. was never done by Linux. The invalid (e.g. negative timevals) were
  128. silently converted to more or less random timeouts and intervals.
  129. Until the removal a per boot limited number of warnings is printed
  130. and the timevals are sanitized.
  131. Who: Thomas Gleixner <tglx@linutronix.de>
  132. ---------------------------
  133. What: I2C interface of the it87 driver
  134. When: January 2007
  135. Why: The ISA interface is faster and should be always available. The I2C
  136. probing is also known to cause trouble in at least one case (see
  137. bug #5889.)
  138. Who: Jean Delvare <khali@linux-fr.org>
  139. ---------------------------
  140. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  141. (temporary transition config option provided until then)
  142. The transition config option will also be removed at the same time.
  143. When: before 2.6.19
  144. Why: Unused symbols are both increasing the size of the kernel binary
  145. and are often a sign of "wrong API"
  146. Who: Arjan van de Ven <arjan@linux.intel.com>
  147. ---------------------------
  148. What: mount/umount uevents
  149. When: February 2007
  150. Why: These events are not correct, and do not properly let userspace know
  151. when a file system has been mounted or unmounted. Userspace should
  152. poll the /proc/mounts file instead to detect this properly.
  153. Who: Greg Kroah-Hartman <gregkh@suse.de>
  154. ---------------------------
  155. What: USB driver API moves to EXPORT_SYMBOL_GPL
  156. When: Febuary 2008
  157. Files: include/linux/usb.h, drivers/usb/core/driver.c
  158. Why: The USB subsystem has changed a lot over time, and it has been
  159. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  160. that operate as fast as the USB bus allows. Because of this, the USB
  161. subsystem will not be allowing closed source kernel drivers to
  162. register with it, after this grace period is over. If anyone needs
  163. any help in converting their closed source drivers over to use the
  164. userspace filesystems, please contact the
  165. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  166. there will be glad to help you out.
  167. Who: Greg Kroah-Hartman <gregkh@suse.de>
  168. ---------------------------
  169. What: find_trylock_page
  170. When: January 2007
  171. Why: The interface no longer has any callers left in the kernel. It
  172. is an odd interface (compared with other find_*_page functions), in
  173. that it does not take a refcount to the page, only the page lock.
  174. It should be replaced with find_get_page or find_lock_page if possible.
  175. This feature removal can be reevaluated if users of the interface
  176. cannot cleanly use something else.
  177. Who: Nick Piggin <npiggin@suse.de>
  178. ---------------------------
  179. What: Support for the Momentum / PMC-Sierra Jaguar ATX evaluation board
  180. When: September 2006
  181. Why: Does no longer build since quite some time, and was never popular,
  182. due to the platform being replaced by successor models. Apparently
  183. no user base left. It also is one of the last users of
  184. WANT_PAGE_VIRTUAL.
  185. Who: Ralf Baechle <ralf@linux-mips.org>
  186. ---------------------------
  187. What: Support for the Momentum Ocelot, Ocelot 3, Ocelot C and Ocelot G
  188. When: September 2006
  189. Why: Some do no longer build and apparently there is no user base left
  190. for these platforms.
  191. Who: Ralf Baechle <ralf@linux-mips.org>
  192. ---------------------------
  193. What: Support for MIPS Technologies' Altas and SEAD evaluation board
  194. When: September 2006
  195. Why: Some do no longer build and apparently there is no user base left
  196. for these platforms. Hardware out of production since several years.
  197. Who: Ralf Baechle <ralf@linux-mips.org>
  198. ---------------------------
  199. What: Support for the IT8172-based platforms, ITE 8172G and Globespan IVR
  200. When: September 2006
  201. Why: Code does no longer build since at least 2.6.0, apparently there is
  202. no user base left for these platforms. Hardware out of production
  203. since several years and hardly a trace of the manufacturer left on
  204. the net.
  205. Who: Ralf Baechle <ralf@linux-mips.org>
  206. ---------------------------
  207. What: Interrupt only SA_* flags
  208. When: Januar 2007
  209. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  210. out of the signal namespace.
  211. Who: Thomas Gleixner <tglx@linutronix.de>
  212. ---------------------------
  213. What: i2c-ite and i2c-algo-ite drivers
  214. When: September 2006
  215. Why: These drivers never compiled since they were added to the kernel
  216. tree 5 years ago. This feature removal can be reevaluated if
  217. someone shows interest in the drivers, fixes them and takes over
  218. maintenance.
  219. http://marc.theaimsgroup.com/?l=linux-mips&m=115040510817448
  220. Who: Jean Delvare <khali@linux-fr.org>
  221. ---------------------------
  222. What: Bridge netfilter deferred IPv4/IPv6 output hook calling
  223. When: January 2007
  224. Why: The deferred output hooks are a layering violation causing unusual
  225. and broken behaviour on bridge devices. Examples of things they
  226. break include QoS classifation using the MARK or CLASSIFY targets,
  227. the IPsec policy match and connection tracking with VLANs on a
  228. bridge. Their only use is to enable bridge output port filtering
  229. within iptables with the physdev match, which can also be done by
  230. combining iptables and ebtables using netfilter marks. Until it
  231. will get removed the hook deferral is disabled by default and is
  232. only enabled when needed.
  233. Who: Patrick McHardy <kaber@trash.net>
  234. ---------------------------
  235. What: frame diverter
  236. When: November 2006
  237. Why: The frame diverter is included in most distribution kernels, but is
  238. broken. It does not correctly handle many things:
  239. - IPV6
  240. - non-linear skb's
  241. - network device RCU on removal
  242. - input frames not correctly checked for protocol errors
  243. It also adds allocation overhead even if not enabled.
  244. It is not clear if anyone is still using it.
  245. Who: Stephen Hemminger <shemminger@osdl.org>
  246. ---------------------------
  247. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  248. When: Oktober 2008
  249. Why: The stacking of class devices makes these values misleading and
  250. inconsistent.
  251. Class devices should not carry any of these properties, and bus
  252. devices have SUBSYTEM and DRIVER as a replacement.
  253. Who: Kay Sievers <kay.sievers@suse.de>
  254. ---------------------------
  255. What: i2c-isa
  256. When: December 2006
  257. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  258. model. Drivers relying on it are better implemented as platform
  259. drivers.
  260. Who: Jean Delvare <khali@linux-fr.org>
  261. ---------------------------