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: 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: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  44. When: December 2006
  45. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  46. series. The old API have lots of drawbacks and don't provide enough
  47. means to work with all video and audio standards. The newer API is
  48. already available on the main drivers and should be used instead.
  49. Newer drivers should use v4l_compat_translate_ioctl function to handle
  50. old calls, replacing to newer ones.
  51. Decoder iocts are using internally to allow video drivers to
  52. communicate with video decoders. This should also be improved to allow
  53. V4L2 calls being translated into compatible internal ioctls.
  54. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  55. ---------------------------
  56. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  57. When: November 2005
  58. Files: drivers/pcmcia/: pcmcia_ioctl.c
  59. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  60. normal hotpluggable bus, and with it using the default kernel
  61. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  62. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  63. unnecessary, and makes further cleanups and integration of the
  64. PCMCIA subsystem into the Linux kernel device driver model more
  65. difficult. The features provided by cardmgr and cardctl are either
  66. handled by the kernel itself now or are available in the new
  67. pcmciautils package available at
  68. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  69. Who: Dominik Brodowski <linux@brodo.de>
  70. ---------------------------
  71. What: remove EXPORT_SYMBOL(kernel_thread)
  72. When: August 2006
  73. Files: arch/*/kernel/*_ksyms.c
  74. Why: kernel_thread is a low-level implementation detail. Drivers should
  75. use the <linux/kthread.h> API instead which shields them from
  76. implementation details and provides a higherlevel interface that
  77. prevents bugs and code duplication
  78. Who: Christoph Hellwig <hch@lst.de>
  79. ---------------------------
  80. What: CONFIG_FORCED_INLINING
  81. When: June 2006
  82. Why: Config option is there to see if gcc is good enough. (in january
  83. 2006). If it is, the behavior should just be the default. If it's not,
  84. the option should just go away entirely.
  85. Who: Arjan van de Ven
  86. ---------------------------
  87. What: eepro100 network driver
  88. When: January 2007
  89. Why: replaced by the e100 driver
  90. Who: Adrian Bunk <bunk@stusta.de>
  91. ---------------------------
  92. What: drivers depending on OSS_OBSOLETE_DRIVER
  93. When: options in 2.6.20, code in 2.6.22
  94. Why: OSS drivers with ALSA replacements
  95. Who: Adrian Bunk <bunk@stusta.de>
  96. ---------------------------
  97. What: pci_module_init(driver)
  98. When: January 2007
  99. Why: Is replaced by pci_register_driver(pci_driver).
  100. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  101. ---------------------------
  102. What: Usage of invalid timevals in setitimer
  103. When: March 2007
  104. Why: POSIX requires to validate timevals in the setitimer call. This
  105. was never done by Linux. The invalid (e.g. negative timevals) were
  106. silently converted to more or less random timeouts and intervals.
  107. Until the removal a per boot limited number of warnings is printed
  108. and the timevals are sanitized.
  109. Who: Thomas Gleixner <tglx@linutronix.de>
  110. ---------------------------
  111. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  112. (temporary transition config option provided until then)
  113. The transition config option will also be removed at the same time.
  114. When: before 2.6.19
  115. Why: Unused symbols are both increasing the size of the kernel binary
  116. and are often a sign of "wrong API"
  117. Who: Arjan van de Ven <arjan@linux.intel.com>
  118. ---------------------------
  119. What: mount/umount uevents
  120. When: February 2007
  121. Why: These events are not correct, and do not properly let userspace know
  122. when a file system has been mounted or unmounted. Userspace should
  123. poll the /proc/mounts file instead to detect this properly.
  124. Who: Greg Kroah-Hartman <gregkh@suse.de>
  125. ---------------------------
  126. What: USB driver API moves to EXPORT_SYMBOL_GPL
  127. When: February 2008
  128. Files: include/linux/usb.h, drivers/usb/core/driver.c
  129. Why: The USB subsystem has changed a lot over time, and it has been
  130. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  131. that operate as fast as the USB bus allows. Because of this, the USB
  132. subsystem will not be allowing closed source kernel drivers to
  133. register with it, after this grace period is over. If anyone needs
  134. any help in converting their closed source drivers over to use the
  135. userspace filesystems, please contact the
  136. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  137. there will be glad to help you out.
  138. Who: Greg Kroah-Hartman <gregkh@suse.de>
  139. ---------------------------
  140. What: Interrupt only SA_* flags
  141. When: Januar 2007
  142. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  143. out of the signal namespace.
  144. Who: Thomas Gleixner <tglx@linutronix.de>
  145. ---------------------------
  146. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  147. When: October 2008
  148. Why: The stacking of class devices makes these values misleading and
  149. inconsistent.
  150. Class devices should not carry any of these properties, and bus
  151. devices have SUBSYTEM and DRIVER as a replacement.
  152. Who: Kay Sievers <kay.sievers@suse.de>
  153. ---------------------------
  154. What: i2c-isa
  155. When: December 2006
  156. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  157. model. Drivers relying on it are better implemented as platform
  158. drivers.
  159. Who: Jean Delvare <khali@linux-fr.org>
  160. ---------------------------
  161. What: i2c_adapter.dev
  162. i2c_adapter.list
  163. When: July 2007
  164. Why: Superfluous, given i2c_adapter.class_dev:
  165. * The "dev" was a stand-in for the physical device node that legacy
  166. drivers would not have; but now it's almost always present. Any
  167. remaining legacy drivers must upgrade (they now trigger warnings).
  168. * The "list" duplicates class device children.
  169. The delay in removing this is so upgraded lm_sensors and libsensors
  170. can get deployed. (Removal causes minor changes in the sysfs layout,
  171. notably the location of the adapter type name and parenting the i2c
  172. client hardware directly from their controller.)
  173. Who: Jean Delvare <khali@linux-fr.org>,
  174. David Brownell <dbrownell@users.sourceforge.net>
  175. ---------------------------
  176. What: drivers depending on OBSOLETE_OSS
  177. When: options in 2.6.22, code in 2.6.24
  178. Why: OSS drivers with ALSA replacements
  179. Who: Adrian Bunk <bunk@stusta.de>
  180. ---------------------------
  181. What: IPv4 only connection tracking/NAT/helpers
  182. When: 2.6.22
  183. Why: The new layer 3 independant connection tracking replaces the old
  184. IPv4 only version. After some stabilization of the new code the
  185. old one will be removed.
  186. Who: Patrick McHardy <kaber@trash.net>
  187. ---------------------------
  188. What: ACPI hooks (X86_SPEEDSTEP_CENTRINO_ACPI) in speedstep-centrino driver
  189. When: December 2006
  190. Why: Speedstep-centrino driver with ACPI hooks and acpi-cpufreq driver are
  191. functionally very much similar. They talk to ACPI in same way. Only
  192. difference between them is the way they do frequency transitions.
  193. One uses MSRs and the other one uses IO ports. Functionaliy of
  194. speedstep_centrino with ACPI hooks is now merged into acpi-cpufreq.
  195. That means one common driver will support all Intel Enhanced Speedstep
  196. capable CPUs. That means less confusion over name of
  197. speedstep-centrino driver (with that driver supposed to be used on
  198. non-centrino platforms). That means less duplication of code and
  199. less maintenance effort and no possibility of these two drivers
  200. going out of sync.
  201. Current users of speedstep_centrino with ACPI hooks are requested to
  202. switch over to acpi-cpufreq driver. speedstep-centrino will continue
  203. to work using older non-ACPI static table based scheme even after this
  204. date.
  205. Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  206. ---------------------------
  207. <<<<<<< test:Documentation/feature-removal-schedule.txt
  208. What: ACPI hotkey driver (CONFIG_ACPI_HOTKEY)
  209. When: 2.6.21
  210. Why: hotkey.c was an attempt to consolidate multiple drivers that use
  211. ACPI to implement hotkeys. However, hotkeys are not documented
  212. in the ACPI specification, so the drivers used undocumented
  213. vendor-specific hooks and turned out to be more different than
  214. the same.
  215. Further, the keys and the features supplied by each platform
  216. are different, so there will always be a need for
  217. platform-specific drivers.
  218. So the new plan is to delete hotkey.c and instead, work on the
  219. platform specific drivers to try to make them look the same
  220. to the user when they supply the same features.
  221. hotkey.c has always depended on CONFIG_EXPERIMENTAL
  222. Who: Len Brown <len.brown@intel.com>
  223. ---------------------------
  224. What: /sys/firmware/acpi/namespace
  225. When: 2.6.21
  226. Why: The ACPI namespace is effectively the symbol list for
  227. the BIOS. The device names are completely arbitrary
  228. and have no place being exposed to user-space.
  229. For those interested in the BIOS ACPI namespace,
  230. the BIOS can be extracted and disassembled with acpidump
  231. and iasl as documented in the pmtools package here:
  232. http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
  233. Who: Len Brown <len.brown@intel.com>
  234. ---------------------------
  235. What: ACPI procfs interface
  236. When: July 2007
  237. Why: After ACPI sysfs conversion, ACPI attributes will be duplicated
  238. in sysfs and the ACPI procfs interface should be removed.
  239. Who: Zhang Rui <rui.zhang@intel.com>
  240. ---------------------------
  241. What: /proc/acpi/button
  242. When: August 2007
  243. Why: /proc/acpi/button has been replaced by events to the input layer
  244. since 2.6.20.
  245. Who: Len Brown <len.brown@intel.com>
  246. ---------------------------
  247. What: JFFS (version 1)
  248. When: 2.6.21
  249. Why: Unmaintained for years, superceded by JFFS2 for years.
  250. Who: Jeff Garzik <jeff@garzik.org>
  251. ---------------------------
  252. What: sk98lin network driver
  253. When: July 2007
  254. Why: In kernel tree version of driver is unmaintained. Sk98lin driver
  255. replaced by the skge driver.
  256. Who: Stephen Hemminger <shemminger@osdl.org>
  257. ---------------------------
  258. What: Compaq touchscreen device emulation
  259. When: Oct 2007
  260. Files: drivers/input/tsdev.c
  261. Why: The code says it was obsolete when it was written in 2001.
  262. tslib is a userspace library which does anything tsdev can do and
  263. much more besides in userspace where this code belongs. There is no
  264. longer any need for tsdev and applications should have converted to
  265. use tslib by now.
  266. The name "tsdev" is also extremely confusing and lots of people have
  267. it loaded when they don't need/use it.
  268. Who: Richard Purdie <rpurdie@rpsys.net>
  269. ---------------------------