feature-removal-schedule.txt 11 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: eepro100 network driver
  103. When: January 2007
  104. Why: replaced by the e100 driver
  105. Who: Adrian Bunk <bunk@stusta.de>
  106. ---------------------------
  107. What: drivers depending on OSS_OBSOLETE_DRIVER
  108. When: options in 2.6.20, code in 2.6.22
  109. Why: OSS drivers with ALSA replacements
  110. Who: Adrian Bunk <bunk@stusta.de>
  111. ---------------------------
  112. What: pci_module_init(driver)
  113. When: January 2007
  114. Why: Is replaced by pci_register_driver(pci_driver).
  115. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  116. ---------------------------
  117. What: Usage of invalid timevals in setitimer
  118. When: March 2007
  119. Why: POSIX requires to validate timevals in the setitimer call. This
  120. was never done by Linux. The invalid (e.g. negative timevals) were
  121. silently converted to more or less random timeouts and intervals.
  122. Until the removal a per boot limited number of warnings is printed
  123. and the timevals are sanitized.
  124. Who: Thomas Gleixner <tglx@linutronix.de>
  125. ---------------------------
  126. What: I2C interface of the it87 driver
  127. When: January 2007
  128. Why: The ISA interface is faster and should be always available. The I2C
  129. probing is also known to cause trouble in at least one case (see
  130. bug #5889.)
  131. Who: Jean Delvare <khali@linux-fr.org>
  132. ---------------------------
  133. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  134. (temporary transition config option provided until then)
  135. The transition config option will also be removed at the same time.
  136. When: before 2.6.19
  137. Why: Unused symbols are both increasing the size of the kernel binary
  138. and are often a sign of "wrong API"
  139. Who: Arjan van de Ven <arjan@linux.intel.com>
  140. ---------------------------
  141. What: mount/umount uevents
  142. When: February 2007
  143. Why: These events are not correct, and do not properly let userspace know
  144. when a file system has been mounted or unmounted. Userspace should
  145. poll the /proc/mounts file instead to detect this properly.
  146. Who: Greg Kroah-Hartman <gregkh@suse.de>
  147. ---------------------------
  148. What: USB driver API moves to EXPORT_SYMBOL_GPL
  149. When: Febuary 2008
  150. Files: include/linux/usb.h, drivers/usb/core/driver.c
  151. Why: The USB subsystem has changed a lot over time, and it has been
  152. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  153. that operate as fast as the USB bus allows. Because of this, the USB
  154. subsystem will not be allowing closed source kernel drivers to
  155. register with it, after this grace period is over. If anyone needs
  156. any help in converting their closed source drivers over to use the
  157. userspace filesystems, please contact the
  158. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  159. there will be glad to help you out.
  160. Who: Greg Kroah-Hartman <gregkh@suse.de>
  161. ---------------------------
  162. What: find_trylock_page
  163. When: January 2007
  164. Why: The interface no longer has any callers left in the kernel. It
  165. is an odd interface (compared with other find_*_page functions), in
  166. that it does not take a refcount to the page, only the page lock.
  167. It should be replaced with find_get_page or find_lock_page if possible.
  168. This feature removal can be reevaluated if users of the interface
  169. cannot cleanly use something else.
  170. Who: Nick Piggin <npiggin@suse.de>
  171. ---------------------------
  172. What: Support for MIPS Technologies' Altas and SEAD evaluation board
  173. When: September 2006
  174. Why: Some do no longer build and apparently there is no user base left
  175. for these platforms. Hardware out of production since several years.
  176. Who: Ralf Baechle <ralf@linux-mips.org>
  177. ---------------------------
  178. What: Support for the IT8172-based platforms, ITE 8172G and Globespan IVR
  179. When: September 2006
  180. Why: Code does no longer build since at least 2.6.0, apparently there is
  181. no user base left for these platforms. Hardware out of production
  182. since several years and hardly a trace of the manufacturer left on
  183. the net.
  184. Who: Ralf Baechle <ralf@linux-mips.org>
  185. ---------------------------
  186. What: Interrupt only SA_* flags
  187. When: Januar 2007
  188. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  189. out of the signal namespace.
  190. Who: Thomas Gleixner <tglx@linutronix.de>
  191. ---------------------------
  192. What: i2c-ite and i2c-algo-ite drivers
  193. When: September 2006
  194. Why: These drivers never compiled since they were added to the kernel
  195. tree 5 years ago. This feature removal can be reevaluated if
  196. someone shows interest in the drivers, fixes them and takes over
  197. maintenance.
  198. http://marc.theaimsgroup.com/?l=linux-mips&m=115040510817448
  199. Who: Jean Delvare <khali@linux-fr.org>
  200. ---------------------------
  201. What: Bridge netfilter deferred IPv4/IPv6 output hook calling
  202. When: January 2007
  203. Why: The deferred output hooks are a layering violation causing unusual
  204. and broken behaviour on bridge devices. Examples of things they
  205. break include QoS classifation using the MARK or CLASSIFY targets,
  206. the IPsec policy match and connection tracking with VLANs on a
  207. bridge. Their only use is to enable bridge output port filtering
  208. within iptables with the physdev match, which can also be done by
  209. combining iptables and ebtables using netfilter marks. Until it
  210. will get removed the hook deferral is disabled by default and is
  211. only enabled when needed.
  212. Who: Patrick McHardy <kaber@trash.net>
  213. ---------------------------
  214. What: frame diverter
  215. When: November 2006
  216. Why: The frame diverter is included in most distribution kernels, but is
  217. broken. It does not correctly handle many things:
  218. - IPV6
  219. - non-linear skb's
  220. - network device RCU on removal
  221. - input frames not correctly checked for protocol errors
  222. It also adds allocation overhead even if not enabled.
  223. It is not clear if anyone is still using it.
  224. Who: Stephen Hemminger <shemminger@osdl.org>
  225. ---------------------------
  226. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  227. When: Oktober 2008
  228. Why: The stacking of class devices makes these values misleading and
  229. inconsistent.
  230. Class devices should not carry any of these properties, and bus
  231. devices have SUBSYTEM and DRIVER as a replacement.
  232. Who: Kay Sievers <kay.sievers@suse.de>
  233. ---------------------------
  234. What: i2c-isa
  235. When: December 2006
  236. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  237. model. Drivers relying on it are better implemented as platform
  238. drivers.
  239. Who: Jean Delvare <khali@linux-fr.org>
  240. ---------------------------
  241. What: ftape
  242. When: 2.6.20
  243. Why: Orphaned for ages. SMP bugs long unfixed. Few users left
  244. in the world.
  245. Who: Jeff Garzik <jeff@garzik.org>
  246. ---------------------------