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: MXSER
  8. When: December 2007
  9. Why: Old mxser driver is obsoleted by the mxser_new. Give it some time yet
  10. and remove it.
  11. Who: Jiri Slaby <jirislaby@gmail.com>
  12. ---------------------------
  13. What: V4L2 VIDIOC_G_MPEGCOMP and VIDIOC_S_MPEGCOMP
  14. When: October 2007
  15. Why: Broken attempt to set MPEG compression parameters. These ioctls are
  16. not able to implement the wide variety of parameters that can be set
  17. by hardware MPEG encoders. A new MPEG control mechanism was created
  18. in kernel 2.6.18 that replaces these ioctls. See the V4L2 specification
  19. (section 1.9: Extended controls) for more information on this topic.
  20. Who: Hans Verkuil <hverkuil@xs4all.nl> and
  21. Mauro Carvalho Chehab <mchehab@infradead.org>
  22. ---------------------------
  23. What: /sys/devices/.../power/state
  24. dev->power.power_state
  25. dpm_runtime_{suspend,resume)()
  26. When: July 2007
  27. Why: Broken design for runtime control over driver power states, confusing
  28. driver-internal runtime power management with: mechanisms to support
  29. system-wide sleep state transitions; event codes that distinguish
  30. different phases of swsusp "sleep" transitions; and userspace policy
  31. inputs. This framework was never widely used, and most attempts to
  32. use it were broken. Drivers should instead be exposing domain-specific
  33. interfaces either to kernel or to userspace.
  34. Who: Pavel Machek <pavel@suse.cz>
  35. ---------------------------
  36. What: RAW driver (CONFIG_RAW_DRIVER)
  37. When: December 2005
  38. Why: declared obsolete since kernel 2.6.3
  39. O_DIRECT can be used instead
  40. Who: Adrian Bunk <bunk@stusta.de>
  41. ---------------------------
  42. What: old NCR53C9x driver
  43. When: October 2007
  44. Why: Replaced by the much better esp_scsi driver. Actual low-level
  45. driver can be ported over almost trivially.
  46. Who: David Miller <davem@davemloft.net>
  47. Christoph Hellwig <hch@lst.de>
  48. ---------------------------
  49. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  50. When: December 2006
  51. Files: include/linux/video_decoder.h
  52. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  53. series. The old API have lots of drawbacks and don't provide enough
  54. means to work with all video and audio standards. The newer API is
  55. already available on the main drivers and should be used instead.
  56. Newer drivers should use v4l_compat_translate_ioctl function to handle
  57. old calls, replacing to newer ones.
  58. Decoder iocts are using internally to allow video drivers to
  59. communicate with video decoders. This should also be improved to allow
  60. V4L2 calls being translated into compatible internal ioctls.
  61. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  62. ---------------------------
  63. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  64. When: November 2005
  65. Files: drivers/pcmcia/: pcmcia_ioctl.c
  66. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  67. normal hotpluggable bus, and with it using the default kernel
  68. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  69. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  70. unnecessary, and makes further cleanups and integration of the
  71. PCMCIA subsystem into the Linux kernel device driver model more
  72. difficult. The features provided by cardmgr and cardctl are either
  73. handled by the kernel itself now or are available in the new
  74. pcmciautils package available at
  75. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  76. Who: Dominik Brodowski <linux@brodo.de>
  77. ---------------------------
  78. What: remove EXPORT_SYMBOL(kernel_thread)
  79. When: August 2006
  80. Files: arch/*/kernel/*_ksyms.c
  81. Funcs: kernel_thread
  82. Why: kernel_thread is a low-level implementation detail. Drivers should
  83. use the <linux/kthread.h> API instead which shields them from
  84. implementation details and provides a higherlevel interface that
  85. prevents bugs and code duplication
  86. Who: Christoph Hellwig <hch@lst.de>
  87. ---------------------------
  88. What: CONFIG_FORCED_INLINING
  89. When: June 2006
  90. Why: Config option is there to see if gcc is good enough. (in january
  91. 2006). If it is, the behavior should just be the default. If it's not,
  92. the option should just go away entirely.
  93. Who: Arjan van de Ven
  94. ---------------------------
  95. What: eepro100 network driver
  96. When: January 2007
  97. Why: replaced by the e100 driver
  98. Who: Adrian Bunk <bunk@stusta.de>
  99. ---------------------------
  100. What: drivers depending on OSS_OBSOLETE_DRIVER
  101. When: options in 2.6.20, code in 2.6.22
  102. Why: OSS drivers with ALSA replacements
  103. Who: Adrian Bunk <bunk@stusta.de>
  104. ---------------------------
  105. What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  106. (temporary transition config option provided until then)
  107. The transition config option will also be removed at the same time.
  108. When: before 2.6.19
  109. Why: Unused symbols are both increasing the size of the kernel binary
  110. and are often a sign of "wrong API"
  111. Who: Arjan van de Ven <arjan@linux.intel.com>
  112. ---------------------------
  113. What: USB driver API moves to EXPORT_SYMBOL_GPL
  114. When: February 2008
  115. Files: include/linux/usb.h, drivers/usb/core/driver.c
  116. Why: The USB subsystem has changed a lot over time, and it has been
  117. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  118. that operate as fast as the USB bus allows. Because of this, the USB
  119. subsystem will not be allowing closed source kernel drivers to
  120. register with it, after this grace period is over. If anyone needs
  121. any help in converting their closed source drivers over to use the
  122. userspace filesystems, please contact the
  123. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  124. there will be glad to help you out.
  125. Who: Greg Kroah-Hartman <gregkh@suse.de>
  126. ---------------------------
  127. What: Interrupt only SA_* flags
  128. When: September 2007
  129. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  130. out of the signal namespace.
  131. Who: Thomas Gleixner <tglx@linutronix.de>
  132. ---------------------------
  133. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  134. When: October 2008
  135. Why: The stacking of class devices makes these values misleading and
  136. inconsistent.
  137. Class devices should not carry any of these properties, and bus
  138. devices have SUBSYTEM and DRIVER as a replacement.
  139. Who: Kay Sievers <kay.sievers@suse.de>
  140. ---------------------------
  141. What: i2c-isa
  142. When: December 2006
  143. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  144. model. Drivers relying on it are better implemented as platform
  145. drivers.
  146. Who: Jean Delvare <khali@linux-fr.org>
  147. ---------------------------
  148. What: i2c_adapter.list
  149. When: July 2007
  150. Why: Superfluous, this list duplicates the one maintained by the driver
  151. core.
  152. Who: Jean Delvare <khali@linux-fr.org>,
  153. David Brownell <dbrownell@users.sourceforge.net>
  154. ---------------------------
  155. What: drivers depending on OBSOLETE_OSS
  156. When: options in 2.6.22, code in 2.6.24
  157. Why: OSS drivers with ALSA replacements
  158. Who: Adrian Bunk <bunk@stusta.de>
  159. ---------------------------
  160. What: /sys/firmware/acpi/namespace
  161. When: 2.6.21
  162. Why: The ACPI namespace is effectively the symbol list for
  163. the BIOS. The device names are completely arbitrary
  164. and have no place being exposed to user-space.
  165. For those interested in the BIOS ACPI namespace,
  166. the BIOS can be extracted and disassembled with acpidump
  167. and iasl as documented in the pmtools package here:
  168. http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
  169. Who: Len Brown <len.brown@intel.com>
  170. ---------------------------
  171. What: ACPI procfs interface
  172. When: July 2007
  173. Why: After ACPI sysfs conversion, ACPI attributes will be duplicated
  174. in sysfs and the ACPI procfs interface should be removed.
  175. Who: Zhang Rui <rui.zhang@intel.com>
  176. ---------------------------
  177. What: /proc/acpi/button
  178. When: August 2007
  179. Why: /proc/acpi/button has been replaced by events to the input layer
  180. since 2.6.20.
  181. Who: Len Brown <len.brown@intel.com>
  182. ---------------------------
  183. What: Compaq touchscreen device emulation
  184. When: Oct 2007
  185. Files: drivers/input/tsdev.c
  186. Why: The code says it was obsolete when it was written in 2001.
  187. tslib is a userspace library which does anything tsdev can do and
  188. much more besides in userspace where this code belongs. There is no
  189. longer any need for tsdev and applications should have converted to
  190. use tslib by now.
  191. The name "tsdev" is also extremely confusing and lots of people have
  192. it loaded when they don't need/use it.
  193. Who: Richard Purdie <rpurdie@rpsys.net>
  194. ---------------------------
  195. What: read_dev_chars(), read_conf_data{,_lpm}() (s390 common I/O layer)
  196. When: December 2007
  197. Why: These functions are a leftover from 2.4 times. They have several
  198. problems:
  199. - Duplication of checks that are done in the device driver's
  200. interrupt handler
  201. - common I/O layer can't do device specific error recovery
  202. - device driver can't be notified for conditions happening during
  203. execution of the function
  204. Device drivers should issue the read device characteristics and read
  205. configuration data ccws and do the appropriate error handling
  206. themselves.
  207. Who: Cornelia Huck <cornelia.huck@de.ibm.com>
  208. ---------------------------
  209. What: i2c-ixp2000, i2c-ixp4xx and scx200_i2c drivers
  210. When: September 2007
  211. Why: Obsolete. The new i2c-gpio driver replaces all hardware-specific
  212. I2C-over-GPIO drivers.
  213. Who: Jean Delvare <khali@linux-fr.org>
  214. ---------------------------
  215. What: drivers depending on OSS_OBSOLETE
  216. When: options in 2.6.23, code in 2.6.25
  217. Why: obsolete OSS drivers
  218. Who: Adrian Bunk <bunk@stusta.de>
  219. ---------------------------
  220. What: libata spindown skipping and warning
  221. When: Dec 2008
  222. Why: Some halt(8) implementations synchronize caches for and spin
  223. down libata disks because libata didn't use to spin down disk on
  224. system halt (only synchronized caches).
  225. Spin down on system halt is now implemented. sysfs node
  226. /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
  227. spin down support is available.
  228. Because issuing spin down command to an already spun down disk
  229. makes some disks spin up just to spin down again, libata tracks
  230. device spindown status to skip the extra spindown command and
  231. warn about it.
  232. This is to give userspace tools the time to get updated and will
  233. be removed after userspace is reasonably updated.
  234. Who: Tejun Heo <htejun@gmail.com>
  235. ---------------------------
  236. What: Legacy RTC drivers (under drivers/i2c/chips)
  237. When: November 2007
  238. Why: Obsolete. We have a RTC subsystem with better drivers.
  239. Who: Jean Delvare <khali@linux-fr.org>
  240. ---------------------------
  241. What: iptables SAME target
  242. When: 1.1. 2008
  243. Files: net/ipv4/netfilter/ipt_SAME.c, include/linux/netfilter_ipv4/ipt_SAME.h
  244. Why: Obsolete for multiple years now, NAT core provides the same behaviour.
  245. Unfixable broken wrt. 32/64 bit cleanness.
  246. Who: Patrick McHardy <kaber@trash.net>
  247. ---------------------------