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: V4L2 VIDIOC_G_MPEGCOMP and VIDIOC_S_MPEGCOMP
  8. When: October 2007
  9. Why: Broken attempt to set MPEG compression parameters. These ioctls are
  10. not able to implement the wide variety of parameters that can be set
  11. by hardware MPEG encoders. A new MPEG control mechanism was created
  12. in kernel 2.6.18 that replaces these ioctls. See the V4L2 specification
  13. (section 1.9: Extended controls) for more information on this topic.
  14. Who: Hans Verkuil <hverkuil@xs4all.nl> and
  15. Mauro Carvalho Chehab <mchehab@infradead.org>
  16. ---------------------------
  17. What: /sys/devices/.../power/state
  18. dev->power.power_state
  19. dpm_runtime_{suspend,resume)()
  20. When: July 2007
  21. Why: Broken design for runtime control over driver power states, confusing
  22. driver-internal runtime power management with: mechanisms to support
  23. system-wide sleep state transitions; event codes that distinguish
  24. different phases of swsusp "sleep" transitions; and userspace policy
  25. inputs. This framework was never widely used, and most attempts to
  26. use it were broken. Drivers should instead be exposing domain-specific
  27. interfaces either to kernel or to userspace.
  28. Who: Pavel Machek <pavel@suse.cz>
  29. ---------------------------
  30. What: RAW driver (CONFIG_RAW_DRIVER)
  31. When: December 2005
  32. Why: declared obsolete since kernel 2.6.3
  33. O_DIRECT can be used instead
  34. Who: Adrian Bunk <bunk@stusta.de>
  35. ---------------------------
  36. What: raw1394: requests of type RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN
  37. When: June 2007
  38. Why: Deprecated in favour of the more efficient and robust rawiso interface.
  39. Affected are applications which use the deprecated part of libraw1394
  40. (raw1394_iso_write, raw1394_start_iso_write, raw1394_start_iso_rcv,
  41. raw1394_stop_iso_rcv) or bypass libraw1394.
  42. Who: Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
  43. ---------------------------
  44. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  45. When: December 2006
  46. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  47. series. The old API have lots of drawbacks and don't provide enough
  48. means to work with all video and audio standards. The newer API is
  49. already available on the main drivers and should be used instead.
  50. Newer drivers should use v4l_compat_translate_ioctl function to handle
  51. old calls, replacing to newer ones.
  52. Decoder iocts are using internally to allow video drivers to
  53. communicate with video decoders. This should also be improved to allow
  54. V4L2 calls being translated into compatible internal ioctls.
  55. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  56. ---------------------------
  57. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  58. When: November 2005
  59. Files: drivers/pcmcia/: pcmcia_ioctl.c
  60. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  61. normal hotpluggable bus, and with it using the default kernel
  62. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  63. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  64. unnecessary, and makes further cleanups and integration of the
  65. PCMCIA subsystem into the Linux kernel device driver model more
  66. difficult. The features provided by cardmgr and cardctl are either
  67. handled by the kernel itself now or are available in the new
  68. pcmciautils package available at
  69. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  70. Who: Dominik Brodowski <linux@brodo.de>
  71. ---------------------------
  72. What: remove EXPORT_SYMBOL(kernel_thread)
  73. When: August 2006
  74. Files: arch/*/kernel/*_ksyms.c
  75. Why: kernel_thread is a low-level implementation detail. Drivers should
  76. use the <linux/kthread.h> API instead which shields them from
  77. implementation details and provides a higherlevel interface that
  78. prevents bugs and code duplication
  79. Who: Christoph Hellwig <hch@lst.de>
  80. ---------------------------
  81. What: CONFIG_FORCED_INLINING
  82. When: June 2006
  83. Why: Config option is there to see if gcc is good enough. (in january
  84. 2006). If it is, the behavior should just be the default. If it's not,
  85. the option should just go away entirely.
  86. Who: Arjan van de Ven
  87. ---------------------------
  88. What: eepro100 network driver
  89. When: January 2007
  90. Why: replaced by the e100 driver
  91. Who: Adrian Bunk <bunk@stusta.de>
  92. ---------------------------
  93. What: drivers depending on OSS_OBSOLETE_DRIVER
  94. When: options in 2.6.20, code in 2.6.22
  95. Why: OSS drivers with ALSA replacements
  96. Who: Adrian Bunk <bunk@stusta.de>
  97. ---------------------------
  98. What: pci_module_init(driver)
  99. When: January 2007
  100. Why: Is replaced by pci_register_driver(pci_driver).
  101. Who: Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
  102. ---------------------------
  103. What: Usage of invalid timevals in setitimer
  104. When: March 2007
  105. Why: POSIX requires to validate timevals in the setitimer call. This
  106. was never done by Linux. The invalid (e.g. negative timevals) were
  107. silently converted to more or less random timeouts and intervals.
  108. Until the removal a per boot limited number of warnings is printed
  109. and the timevals are sanitized.
  110. Who: Thomas Gleixner <tglx@linutronix.de>
  111. ---------------------------
  112. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  113. (temporary transition config option provided until then)
  114. The transition config option will also be removed at the same time.
  115. When: before 2.6.19
  116. Why: Unused symbols are both increasing the size of the kernel binary
  117. and are often a sign of "wrong API"
  118. Who: Arjan van de Ven <arjan@linux.intel.com>
  119. ---------------------------
  120. What: mount/umount uevents
  121. When: February 2007
  122. Why: These events are not correct, and do not properly let userspace know
  123. when a file system has been mounted or unmounted. Userspace should
  124. poll the /proc/mounts file instead to detect this properly.
  125. Who: Greg Kroah-Hartman <gregkh@suse.de>
  126. ---------------------------
  127. What: USB driver API moves to EXPORT_SYMBOL_GPL
  128. When: February 2008
  129. Files: include/linux/usb.h, drivers/usb/core/driver.c
  130. Why: The USB subsystem has changed a lot over time, and it has been
  131. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  132. that operate as fast as the USB bus allows. Because of this, the USB
  133. subsystem will not be allowing closed source kernel drivers to
  134. register with it, after this grace period is over. If anyone needs
  135. any help in converting their closed source drivers over to use the
  136. userspace filesystems, please contact the
  137. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  138. there will be glad to help you out.
  139. Who: Greg Kroah-Hartman <gregkh@suse.de>
  140. ---------------------------
  141. What: Interrupt only SA_* flags
  142. When: Januar 2007
  143. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  144. out of the signal namespace.
  145. Who: Thomas Gleixner <tglx@linutronix.de>
  146. ---------------------------
  147. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  148. When: October 2008
  149. Why: The stacking of class devices makes these values misleading and
  150. inconsistent.
  151. Class devices should not carry any of these properties, and bus
  152. devices have SUBSYTEM and DRIVER as a replacement.
  153. Who: Kay Sievers <kay.sievers@suse.de>
  154. ---------------------------
  155. What: i2c-isa
  156. When: December 2006
  157. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  158. model. Drivers relying on it are better implemented as platform
  159. drivers.
  160. Who: Jean Delvare <khali@linux-fr.org>
  161. ---------------------------
  162. What: i2c_adapter.dev
  163. i2c_adapter.list
  164. When: July 2007
  165. Why: Superfluous, given i2c_adapter.class_dev:
  166. * The "dev" was a stand-in for the physical device node that legacy
  167. drivers would not have; but now it's almost always present. Any
  168. remaining legacy drivers must upgrade (they now trigger warnings).
  169. * The "list" duplicates class device children.
  170. The delay in removing this is so upgraded lm_sensors and libsensors
  171. can get deployed. (Removal causes minor changes in the sysfs layout,
  172. notably the location of the adapter type name and parenting the i2c
  173. client hardware directly from their controller.)
  174. Who: Jean Delvare <khali@linux-fr.org>,
  175. David Brownell <dbrownell@users.sourceforge.net>
  176. ---------------------------
  177. What: drivers depending on OBSOLETE_OSS
  178. When: options in 2.6.22, code in 2.6.24
  179. Why: OSS drivers with ALSA replacements
  180. Who: Adrian Bunk <bunk@stusta.de>
  181. ---------------------------
  182. What: ACPI hooks (X86_SPEEDSTEP_CENTRINO_ACPI) in speedstep-centrino driver
  183. When: December 2006
  184. Why: Speedstep-centrino driver with ACPI hooks and acpi-cpufreq driver are
  185. functionally very much similar. They talk to ACPI in same way. Only
  186. difference between them is the way they do frequency transitions.
  187. One uses MSRs and the other one uses IO ports. Functionaliy of
  188. speedstep_centrino with ACPI hooks is now merged into acpi-cpufreq.
  189. That means one common driver will support all Intel Enhanced Speedstep
  190. capable CPUs. That means less confusion over name of
  191. speedstep-centrino driver (with that driver supposed to be used on
  192. non-centrino platforms). That means less duplication of code and
  193. less maintenance effort and no possibility of these two drivers
  194. going out of sync.
  195. Current users of speedstep_centrino with ACPI hooks are requested to
  196. switch over to acpi-cpufreq driver. speedstep-centrino will continue
  197. to work using older non-ACPI static table based scheme even after this
  198. date.
  199. Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  200. ---------------------------
  201. What: /sys/firmware/acpi/namespace
  202. When: 2.6.21
  203. Why: The ACPI namespace is effectively the symbol list for
  204. the BIOS. The device names are completely arbitrary
  205. and have no place being exposed to user-space.
  206. For those interested in the BIOS ACPI namespace,
  207. the BIOS can be extracted and disassembled with acpidump
  208. and iasl as documented in the pmtools package here:
  209. http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
  210. Who: Len Brown <len.brown@intel.com>
  211. ---------------------------
  212. What: ACPI procfs interface
  213. When: July 2007
  214. Why: After ACPI sysfs conversion, ACPI attributes will be duplicated
  215. in sysfs and the ACPI procfs interface should be removed.
  216. Who: Zhang Rui <rui.zhang@intel.com>
  217. ---------------------------
  218. What: /proc/acpi/button
  219. When: August 2007
  220. Why: /proc/acpi/button has been replaced by events to the input layer
  221. since 2.6.20.
  222. Who: Len Brown <len.brown@intel.com>
  223. ---------------------------
  224. What: sk98lin network driver
  225. When: July 2007
  226. Why: In kernel tree version of driver is unmaintained. Sk98lin driver
  227. replaced by the skge driver.
  228. Who: Stephen Hemminger <shemminger@osdl.org>
  229. ---------------------------
  230. What: Compaq touchscreen device emulation
  231. When: Oct 2007
  232. Files: drivers/input/tsdev.c
  233. Why: The code says it was obsolete when it was written in 2001.
  234. tslib is a userspace library which does anything tsdev can do and
  235. much more besides in userspace where this code belongs. There is no
  236. longer any need for tsdev and applications should have converted to
  237. use tslib by now.
  238. The name "tsdev" is also extremely confusing and lots of people have
  239. it loaded when they don't need/use it.
  240. Who: Richard Purdie <rpurdie@rpsys.net>
  241. ---------------------------
  242. What: i8xx_tco watchdog driver
  243. When: in 2.6.22
  244. Why: the i8xx_tco watchdog driver has been replaced by the iTCO_wdt
  245. watchdog driver.
  246. Who: Wim Van Sebroeck <wim@iguana.be>
  247. ---------------------------
  248. What: Multipath cached routing support in ipv4
  249. When: in 2.6.23
  250. Why: Code was merged, then submitter immediately disappeared leaving
  251. us with no maintainer and lots of bugs. The code should not have
  252. been merged in the first place, and many aspects of it's
  253. implementation are blocking more critical core networking
  254. development. It's marked EXPERIMENTAL and no distribution
  255. enables it because it cause obscure crashes due to unfixable bugs
  256. (interfaces don't return errors so memory allocation can't be
  257. handled, calling contexts of these interfaces make handling
  258. errors impossible too because they get called after we've
  259. totally commited to creating a route object, for example).
  260. This problem has existed for years and no forward progress
  261. has ever been made, and nobody steps up to try and salvage
  262. this code, so we're going to finally just get rid of it.
  263. Who: David S. Miller <davem@davemloft.net>
  264. ---------------------------