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: sbp2: module parameter "force_inquiry_hack"
  40. When: July 2006
  41. Why: Superceded by parameter "workarounds". Both parameters are meant to be
  42. used ad-hoc and for single devices only, i.e. not in modprobe.conf,
  43. therefore the impact of this feature replacement should be low.
  44. Who: Stefan Richter <stefanr@s5r6.in-berlin.de>
  45. ---------------------------
  46. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  47. When: July 2006
  48. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  49. series. The old API have lots of drawbacks and don't provide enough
  50. means to work with all video and audio standards. The newer API is
  51. already available on the main drivers and should be used instead.
  52. Newer drivers should use v4l_compat_translate_ioctl function to handle
  53. old calls, replacing to newer ones.
  54. Decoder iocts are using internally to allow video drivers to
  55. communicate with video decoders. This should also be improved to allow
  56. V4L2 calls being translated into compatible internal ioctls.
  57. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  58. ---------------------------
  59. What: sys_sysctl
  60. When: January 2007
  61. Why: The same information is available through /proc/sys and that is the
  62. interface user space prefers to use. And there do not appear to be
  63. any existing user in user space of sys_sysctl. The additional
  64. maintenance overhead of keeping a set of binary names gets
  65. in the way of doing a good job of maintaining this interface.
  66. Who: Eric Biederman <ebiederm@xmission.com>
  67. ---------------------------
  68. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  69. When: November 2005
  70. Files: drivers/pcmcia/: pcmcia_ioctl.c
  71. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  72. normal hotpluggable bus, and with it using the default kernel
  73. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  74. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  75. unnecessary, and makes further cleanups and integration of the
  76. PCMCIA subsystem into the Linux kernel device driver model more
  77. difficult. The features provided by cardmgr and cardctl are either
  78. handled by the kernel itself now or are available in the new
  79. pcmciautils package available at
  80. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  81. Who: Dominik Brodowski <linux@brodo.de>
  82. ---------------------------
  83. What: ip_queue and ip6_queue (old ipv4-only and ipv6-only netfilter queue)
  84. When: December 2005
  85. Why: This interface has been obsoleted by the new layer3-independent
  86. "nfnetlink_queue". The Kernel interface is compatible, so the old
  87. ip[6]tables "QUEUE" targets still work and will transparently handle
  88. all packets into nfnetlink queue number 0. Userspace users will have
  89. to link against API-compatible library on top of libnfnetlink_queue
  90. instead of the current 'libipq'.
  91. Who: Harald Welte <laforge@netfilter.org>
  92. ---------------------------
  93. What: remove EXPORT_SYMBOL(kernel_thread)
  94. When: August 2006
  95. Files: arch/*/kernel/*_ksyms.c
  96. Why: kernel_thread is a low-level implementation detail. Drivers should
  97. use the <linux/kthread.h> API instead which shields them from
  98. implementation details and provides a higherlevel interface that
  99. prevents bugs and code duplication
  100. Who: Christoph Hellwig <hch@lst.de>
  101. ---------------------------
  102. What: CONFIG_FORCED_INLINING
  103. When: June 2006
  104. Why: Config option is there to see if gcc is good enough. (in january
  105. 2006). If it is, the behavior should just be the default. If it's not,
  106. the option should just go away entirely.
  107. Who: Arjan van de Ven
  108. ---------------------------
  109. What: START_ARRAY ioctl for md
  110. When: July 2006
  111. Files: drivers/md/md.c
  112. Why: Not reliable by design - can fail when most needed.
  113. Alternatives exist
  114. Who: NeilBrown <neilb@suse.de>
  115. ---------------------------
  116. What: eepro100 network driver
  117. When: January 2007
  118. Why: replaced by the e100 driver
  119. Who: Adrian Bunk <bunk@stusta.de>
  120. ---------------------------
  121. What: drivers depending on OSS_OBSOLETE_DRIVER
  122. When: options in 2.6.20, code in 2.6.22
  123. Why: OSS drivers with ALSA replacements
  124. Who: Adrian Bunk <bunk@stusta.de>
  125. ---------------------------
  126. What: pci_module_init(driver)
  127. When: January 2007
  128. Why: Is replaced by pci_register_driver(pci_driver).
  129. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  130. ---------------------------
  131. What: Usage of invalid timevals in setitimer
  132. When: March 2007
  133. Why: POSIX requires to validate timevals in the setitimer call. This
  134. was never done by Linux. The invalid (e.g. negative timevals) were
  135. silently converted to more or less random timeouts and intervals.
  136. Until the removal a per boot limited number of warnings is printed
  137. and the timevals are sanitized.
  138. Who: Thomas Gleixner <tglx@linutronix.de>
  139. ---------------------------
  140. What: I2C interface of the it87 driver
  141. When: January 2007
  142. Why: The ISA interface is faster and should be always available. The I2C
  143. probing is also known to cause trouble in at least one case (see
  144. bug #5889.)
  145. Who: Jean Delvare <khali@linux-fr.org>
  146. ---------------------------
  147. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  148. (temporary transition config option provided until then)
  149. The transition config option will also be removed at the same time.
  150. When: before 2.6.19
  151. Why: Unused symbols are both increasing the size of the kernel binary
  152. and are often a sign of "wrong API"
  153. Who: Arjan van de Ven <arjan@linux.intel.com>
  154. ---------------------------
  155. What: mount/umount uevents
  156. When: February 2007
  157. Why: These events are not correct, and do not properly let userspace know
  158. when a file system has been mounted or unmounted. Userspace should
  159. poll the /proc/mounts file instead to detect this properly.
  160. Who: Greg Kroah-Hartman <gregkh@suse.de>
  161. ---------------------------
  162. What: USB driver API moves to EXPORT_SYMBOL_GPL
  163. When: Febuary 2008
  164. Files: include/linux/usb.h, drivers/usb/core/driver.c
  165. Why: The USB subsystem has changed a lot over time, and it has been
  166. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  167. that operate as fast as the USB bus allows. Because of this, the USB
  168. subsystem will not be allowing closed source kernel drivers to
  169. register with it, after this grace period is over. If anyone needs
  170. any help in converting their closed source drivers over to use the
  171. userspace filesystems, please contact the
  172. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  173. there will be glad to help you out.
  174. Who: Greg Kroah-Hartman <gregkh@suse.de>
  175. ---------------------------
  176. What: find_trylock_page
  177. When: January 2007
  178. Why: The interface no longer has any callers left in the kernel. It
  179. is an odd interface (compared with other find_*_page functions), in
  180. that it does not take a refcount to the page, only the page lock.
  181. It should be replaced with find_get_page or find_lock_page if possible.
  182. This feature removal can be reevaluated if users of the interface
  183. cannot cleanly use something else.
  184. Who: Nick Piggin <npiggin@suse.de>
  185. ---------------------------
  186. What: Support for the Momentum / PMC-Sierra Jaguar ATX evaluation board
  187. When: September 2006
  188. Why: Does no longer build since quite some time, and was never popular,
  189. due to the platform being replaced by successor models. Apparently
  190. no user base left. It also is one of the last users of
  191. WANT_PAGE_VIRTUAL.
  192. Who: Ralf Baechle <ralf@linux-mips.org>
  193. ---------------------------
  194. What: Support for the Momentum Ocelot, Ocelot 3, Ocelot C and Ocelot G
  195. When: September 2006
  196. Why: Some do no longer build and apparently there is no user base left
  197. for these platforms.
  198. Who: Ralf Baechle <ralf@linux-mips.org>
  199. ---------------------------
  200. What: Support for MIPS Technologies' Altas and SEAD evaluation board
  201. When: September 2006
  202. Why: Some do no longer build and apparently there is no user base left
  203. for these platforms. Hardware out of production since several years.
  204. Who: Ralf Baechle <ralf@linux-mips.org>
  205. ---------------------------
  206. What: Support for the IT8172-based platforms, ITE 8172G and Globespan IVR
  207. When: September 2006
  208. Why: Code does no longer build since at least 2.6.0, apparently there is
  209. no user base left for these platforms. Hardware out of production
  210. since several years and hardly a trace of the manufacturer left on
  211. the net.
  212. Who: Ralf Baechle <ralf@linux-mips.org>
  213. ---------------------------
  214. What: Interrupt only SA_* flags
  215. When: Januar 2007
  216. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  217. out of the signal namespace.
  218. Who: Thomas Gleixner <tglx@linutronix.de>
  219. ---------------------------
  220. What: i2c-ite and i2c-algo-ite drivers
  221. When: September 2006
  222. Why: These drivers never compiled since they were added to the kernel
  223. tree 5 years ago. This feature removal can be reevaluated if
  224. someone shows interest in the drivers, fixes them and takes over
  225. maintenance.
  226. http://marc.theaimsgroup.com/?l=linux-mips&m=115040510817448
  227. Who: Jean Delvare <khali@linux-fr.org>
  228. ---------------------------
  229. What: Bridge netfilter deferred IPv4/IPv6 output hook calling
  230. When: January 2007
  231. Why: The deferred output hooks are a layering violation causing unusual
  232. and broken behaviour on bridge devices. Examples of things they
  233. break include QoS classifation using the MARK or CLASSIFY targets,
  234. the IPsec policy match and connection tracking with VLANs on a
  235. bridge. Their only use is to enable bridge output port filtering
  236. within iptables with the physdev match, which can also be done by
  237. combining iptables and ebtables using netfilter marks. Until it
  238. will get removed the hook deferral is disabled by default and is
  239. only enabled when needed.
  240. Who: Patrick McHardy <kaber@trash.net>
  241. ---------------------------
  242. What: frame diverter
  243. When: November 2006
  244. Why: The frame diverter is included in most distribution kernels, but is
  245. broken. It does not correctly handle many things:
  246. - IPV6
  247. - non-linear skb's
  248. - network device RCU on removal
  249. - input frames not correctly checked for protocol errors
  250. It also adds allocation overhead even if not enabled.
  251. It is not clear if anyone is still using it.
  252. Who: Stephen Hemminger <shemminger@osdl.org>
  253. ---------------------------
  254. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  255. When: Oktober 2008
  256. Why: The stacking of class devices makes these values misleading and
  257. inconsistent.
  258. Class devices should not carry any of these properties, and bus
  259. devices have SUBSYTEM and DRIVER as a replacement.
  260. Who: Kay Sievers <kay.sievers@suse.de>
  261. ---------------------------
  262. What: i2c-isa
  263. When: December 2006
  264. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  265. model. Drivers relying on it are better implemented as platform
  266. drivers.
  267. Who: Jean Delvare <khali@linux-fr.org>
  268. ---------------------------