feature-removal-schedule.txt 12 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319
  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: raw1394: requests of type RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN
  27. When: June 2007
  28. Why: Deprecated in favour of the more efficient and robust rawiso interface.
  29. Affected are applications which use the deprecated part of libraw1394
  30. (raw1394_iso_write, raw1394_start_iso_write, raw1394_start_iso_rcv,
  31. raw1394_stop_iso_rcv) or bypass libraw1394.
  32. Who: Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
  33. ---------------------------
  34. What: dv1394 driver (CONFIG_IEEE1394_DV1394)
  35. When: June 2007
  36. Why: Replaced by raw1394 + userspace libraries, notably libiec61883. This
  37. shift of application support has been indicated on www.linux1394.org
  38. and developers' mailinglists for quite some time. Major applications
  39. have been converted, with the exception of ffmpeg and hence xine.
  40. Piped output of dvgrab2 is a partial equivalent to dv1394.
  41. Who: Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
  42. ---------------------------
  43. What: ieee1394's *_oui sysfs attributes (CONFIG_IEEE1394_OUI_DB)
  44. When: January 2007
  45. Files: drivers/ieee1394/: oui.db, oui2c.sh
  46. Why: big size, little value
  47. Who: Stefan Richter <stefanr@s5r6.in-berlin.de>
  48. ---------------------------
  49. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  50. When: December 2006
  51. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  52. series. The old API have lots of drawbacks and don't provide enough
  53. means to work with all video and audio standards. The newer API is
  54. already available on the main drivers and should be used instead.
  55. Newer drivers should use v4l_compat_translate_ioctl function to handle
  56. old calls, replacing to newer ones.
  57. Decoder iocts are using internally to allow video drivers to
  58. communicate with video decoders. This should also be improved to allow
  59. V4L2 calls being translated into compatible internal ioctls.
  60. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  61. ---------------------------
  62. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  63. When: November 2005
  64. Files: drivers/pcmcia/: pcmcia_ioctl.c
  65. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  66. normal hotpluggable bus, and with it using the default kernel
  67. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  68. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  69. unnecessary, and makes further cleanups and integration of the
  70. PCMCIA subsystem into the Linux kernel device driver model more
  71. difficult. The features provided by cardmgr and cardctl are either
  72. handled by the kernel itself now or are available in the new
  73. pcmciautils package available at
  74. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  75. Who: Dominik Brodowski <linux@brodo.de>
  76. ---------------------------
  77. What: remove EXPORT_SYMBOL(kernel_thread)
  78. When: August 2006
  79. Files: arch/*/kernel/*_ksyms.c
  80. Why: kernel_thread is a low-level implementation detail. Drivers should
  81. use the <linux/kthread.h> API instead which shields them from
  82. implementation details and provides a higherlevel interface that
  83. prevents bugs and code duplication
  84. Who: Christoph Hellwig <hch@lst.de>
  85. ---------------------------
  86. What: CONFIG_FORCED_INLINING
  87. When: June 2006
  88. Why: Config option is there to see if gcc is good enough. (in january
  89. 2006). If it is, the behavior should just be the default. If it's not,
  90. the option should just go away entirely.
  91. Who: Arjan van de Ven
  92. ---------------------------
  93. What: eepro100 network driver
  94. When: January 2007
  95. Why: replaced by the e100 driver
  96. Who: Adrian Bunk <bunk@stusta.de>
  97. ---------------------------
  98. What: drivers depending on OSS_OBSOLETE_DRIVER
  99. When: options in 2.6.20, code in 2.6.22
  100. Why: OSS drivers with ALSA replacements
  101. Who: Adrian Bunk <bunk@stusta.de>
  102. ---------------------------
  103. What: pci_module_init(driver)
  104. When: January 2007
  105. Why: Is replaced by pci_register_driver(pci_driver).
  106. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  107. ---------------------------
  108. What: Usage of invalid timevals in setitimer
  109. When: March 2007
  110. Why: POSIX requires to validate timevals in the setitimer call. This
  111. was never done by Linux. The invalid (e.g. negative timevals) were
  112. silently converted to more or less random timeouts and intervals.
  113. Until the removal a per boot limited number of warnings is printed
  114. and the timevals are sanitized.
  115. Who: Thomas Gleixner <tglx@linutronix.de>
  116. ---------------------------
  117. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  118. (temporary transition config option provided until then)
  119. The transition config option will also be removed at the same time.
  120. When: before 2.6.19
  121. Why: Unused symbols are both increasing the size of the kernel binary
  122. and are often a sign of "wrong API"
  123. Who: Arjan van de Ven <arjan@linux.intel.com>
  124. ---------------------------
  125. What: mount/umount uevents
  126. When: February 2007
  127. Why: These events are not correct, and do not properly let userspace know
  128. when a file system has been mounted or unmounted. Userspace should
  129. poll the /proc/mounts file instead to detect this properly.
  130. Who: Greg Kroah-Hartman <gregkh@suse.de>
  131. ---------------------------
  132. What: USB driver API moves to EXPORT_SYMBOL_GPL
  133. When: February 2008
  134. Files: include/linux/usb.h, drivers/usb/core/driver.c
  135. Why: The USB subsystem has changed a lot over time, and it has been
  136. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  137. that operate as fast as the USB bus allows. Because of this, the USB
  138. subsystem will not be allowing closed source kernel drivers to
  139. register with it, after this grace period is over. If anyone needs
  140. any help in converting their closed source drivers over to use the
  141. userspace filesystems, please contact the
  142. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  143. there will be glad to help you out.
  144. Who: Greg Kroah-Hartman <gregkh@suse.de>
  145. ---------------------------
  146. What: find_trylock_page
  147. When: January 2007
  148. Why: The interface no longer has any callers left in the kernel. It
  149. is an odd interface (compared with other find_*_page functions), in
  150. that it does not take a refcount to the page, only the page lock.
  151. It should be replaced with find_get_page or find_lock_page if possible.
  152. This feature removal can be reevaluated if users of the interface
  153. cannot cleanly use something else.
  154. Who: Nick Piggin <npiggin@suse.de>
  155. ---------------------------
  156. What: Interrupt only SA_* flags
  157. When: Januar 2007
  158. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  159. out of the signal namespace.
  160. Who: Thomas Gleixner <tglx@linutronix.de>
  161. ---------------------------
  162. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  163. When: October 2008
  164. Why: The stacking of class devices makes these values misleading and
  165. inconsistent.
  166. Class devices should not carry any of these properties, and bus
  167. devices have SUBSYTEM and DRIVER as a replacement.
  168. Who: Kay Sievers <kay.sievers@suse.de>
  169. ---------------------------
  170. What: i2c-isa
  171. When: December 2006
  172. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  173. model. Drivers relying on it are better implemented as platform
  174. drivers.
  175. Who: Jean Delvare <khali@linux-fr.org>
  176. ---------------------------
  177. What: i2c_adapter.dev
  178. i2c_adapter.list
  179. When: July 2007
  180. Why: Superfluous, given i2c_adapter.class_dev:
  181. * The "dev" was a stand-in for the physical device node that legacy
  182. drivers would not have; but now it's almost always present. Any
  183. remaining legacy drivers must upgrade (they now trigger warnings).
  184. * The "list" duplicates class device children.
  185. The delay in removing this is so upgraded lm_sensors and libsensors
  186. can get deployed. (Removal causes minor changes in the sysfs layout,
  187. notably the location of the adapter type name and parenting the i2c
  188. client hardware directly from their controller.)
  189. Who: Jean Delvare <khali@linux-fr.org>,
  190. David Brownell <dbrownell@users.sourceforge.net>
  191. ---------------------------
  192. What: IPv4 only connection tracking/NAT/helpers
  193. When: 2.6.22
  194. Why: The new layer 3 independant connection tracking replaces the old
  195. IPv4 only version. After some stabilization of the new code the
  196. old one will be removed.
  197. Who: Patrick McHardy <kaber@trash.net>
  198. ---------------------------
  199. What: ACPI hooks (X86_SPEEDSTEP_CENTRINO_ACPI) in speedstep-centrino driver
  200. When: December 2006
  201. Why: Speedstep-centrino driver with ACPI hooks and acpi-cpufreq driver are
  202. functionally very much similar. They talk to ACPI in same way. Only
  203. difference between them is the way they do frequency transitions.
  204. One uses MSRs and the other one uses IO ports. Functionaliy of
  205. speedstep_centrino with ACPI hooks is now merged into acpi-cpufreq.
  206. That means one common driver will support all Intel Enhanced Speedstep
  207. capable CPUs. That means less confusion over name of
  208. speedstep-centrino driver (with that driver supposed to be used on
  209. non-centrino platforms). That means less duplication of code and
  210. less maintenance effort and no possibility of these two drivers
  211. going out of sync.
  212. Current users of speedstep_centrino with ACPI hooks are requested to
  213. switch over to acpi-cpufreq driver. speedstep-centrino will continue
  214. to work using older non-ACPI static table based scheme even after this
  215. date.
  216. Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  217. ---------------------------
  218. What: ACPI hotkey driver (CONFIG_ACPI_HOTKEY)
  219. When: 2.6.21
  220. Why: hotkey.c was an attempt to consolidate multiple drivers that use
  221. ACPI to implement hotkeys. However, hotkeys are not documented
  222. in the ACPI specification, so the drivers used undocumented
  223. vendor-specific hooks and turned out to be more different than
  224. the same.
  225. Further, the keys and the features supplied by each platform
  226. are different, so there will always be a need for
  227. platform-specific drivers.
  228. So the new plan is to delete hotkey.c and instead, work on the
  229. platform specific drivers to try to make them look the same
  230. to the user when they supply the same features.
  231. hotkey.c has always depended on CONFIG_EXPERIMENTAL
  232. Who: Len Brown <len.brown@intel.com>
  233. ---------------------------
  234. What: /sys/firmware/acpi/namespace
  235. When: 2.6.21
  236. Why: The ACPI namespace is effectively the symbol list for
  237. the BIOS. The device names are completely arbitrary
  238. and have no place being exposed to user-space.
  239. For those interested in the BIOS ACPI namespace,
  240. the BIOS can be extracted and disassembled with acpidump
  241. and iasl as documented in the pmtools package here:
  242. http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
  243. Who: Len Brown <len.brown@intel.com>
  244. ---------------------------
  245. What: /proc/acpi/button
  246. When: August 2007
  247. Why: /proc/acpi/button has been replaced by events to the input layer
  248. since 2.6.20.
  249. Who: Len Brown <len.brown@intel.com>
  250. ---------------------------
  251. What: JFFS (version 1)
  252. When: 2.6.21
  253. Why: Unmaintained for years, superceded by JFFS2 for years.
  254. Who: Jeff Garzik <jeff@garzik.org>
  255. ---------------------------