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: 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: dev->power.power_state
  24. When: July 2007
  25. Why: Broken design for runtime control over driver power states, confusing
  26. driver-internal runtime power management with: mechanisms to support
  27. system-wide sleep state transitions; event codes that distinguish
  28. different phases of swsusp "sleep" transitions; and userspace policy
  29. inputs. This framework was never widely used, and most attempts to
  30. use it were broken. Drivers should instead be exposing domain-specific
  31. interfaces either to kernel or to userspace.
  32. Who: Pavel Machek <pavel@suse.cz>
  33. ---------------------------
  34. What: old NCR53C9x driver
  35. When: October 2007
  36. Why: Replaced by the much better esp_scsi driver. Actual low-level
  37. driver can be ported over almost trivially.
  38. Who: David Miller <davem@davemloft.net>
  39. Christoph Hellwig <hch@lst.de>
  40. ---------------------------
  41. What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  42. When: December 2006
  43. Files: include/linux/video_decoder.h
  44. Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  45. series. The old API have lots of drawbacks and don't provide enough
  46. means to work with all video and audio standards. The newer API is
  47. already available on the main drivers and should be used instead.
  48. Newer drivers should use v4l_compat_translate_ioctl function to handle
  49. old calls, replacing to newer ones.
  50. Decoder iocts are using internally to allow video drivers to
  51. communicate with video decoders. This should also be improved to allow
  52. V4L2 calls being translated into compatible internal ioctls.
  53. Who: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  54. ---------------------------
  55. What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  56. When: November 2005
  57. Files: drivers/pcmcia/: pcmcia_ioctl.c
  58. Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
  59. normal hotpluggable bus, and with it using the default kernel
  60. infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  61. control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  62. unnecessary, and makes further cleanups and integration of the
  63. PCMCIA subsystem into the Linux kernel device driver model more
  64. difficult. The features provided by cardmgr and cardctl are either
  65. handled by the kernel itself now or are available in the new
  66. pcmciautils package available at
  67. http://kernel.org/pub/linux/utils/kernel/pcmcia/
  68. Who: Dominik Brodowski <linux@brodo.de>
  69. ---------------------------
  70. What: remove EXPORT_SYMBOL(kernel_thread)
  71. When: August 2006
  72. Files: arch/*/kernel/*_ksyms.c
  73. Funcs: kernel_thread
  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: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
  93. (temporary transition config option provided until then)
  94. The transition config option will also be removed at the same time.
  95. When: before 2.6.19
  96. Why: Unused symbols are both increasing the size of the kernel binary
  97. and are often a sign of "wrong API"
  98. Who: Arjan van de Ven <arjan@linux.intel.com>
  99. ---------------------------
  100. What: USB driver API moves to EXPORT_SYMBOL_GPL
  101. When: February 2008
  102. Files: include/linux/usb.h, drivers/usb/core/driver.c
  103. Why: The USB subsystem has changed a lot over time, and it has been
  104. possible to create userspace USB drivers using usbfs/libusb/gadgetfs
  105. that operate as fast as the USB bus allows. Because of this, the USB
  106. subsystem will not be allowing closed source kernel drivers to
  107. register with it, after this grace period is over. If anyone needs
  108. any help in converting their closed source drivers over to use the
  109. userspace filesystems, please contact the
  110. linux-usb-devel@lists.sourceforge.net mailing list, and the developers
  111. there will be glad to help you out.
  112. Who: Greg Kroah-Hartman <gregkh@suse.de>
  113. ---------------------------
  114. What: vm_ops.nopage
  115. When: Soon, provided in-kernel callers have been converted
  116. Why: This interface is replaced by vm_ops.fault, but it has been around
  117. forever, is used by a lot of drivers, and doesn't cost much to
  118. maintain.
  119. Who: Nick Piggin <npiggin@suse.de>
  120. ---------------------------
  121. What: Interrupt only SA_* flags
  122. When: September 2007
  123. Why: The interrupt related SA_* flags are replaced by IRQF_* to move them
  124. out of the signal namespace.
  125. Who: Thomas Gleixner <tglx@linutronix.de>
  126. ---------------------------
  127. What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
  128. When: October 2008
  129. Why: The stacking of class devices makes these values misleading and
  130. inconsistent.
  131. Class devices should not carry any of these properties, and bus
  132. devices have SUBSYTEM and DRIVER as a replacement.
  133. Who: Kay Sievers <kay.sievers@suse.de>
  134. ---------------------------
  135. What: i2c-isa
  136. When: December 2006
  137. Why: i2c-isa is a non-sense and doesn't fit in the device driver
  138. model. Drivers relying on it are better implemented as platform
  139. drivers.
  140. Who: Jean Delvare <khali@linux-fr.org>
  141. ---------------------------
  142. What: i2c_adapter.list
  143. When: July 2007
  144. Why: Superfluous, this list duplicates the one maintained by the driver
  145. core.
  146. Who: Jean Delvare <khali@linux-fr.org>,
  147. David Brownell <dbrownell@users.sourceforge.net>
  148. ---------------------------
  149. What: drivers depending on OBSOLETE_OSS
  150. When: options in 2.6.22, code in 2.6.24
  151. Why: OSS drivers with ALSA replacements
  152. Who: Adrian Bunk <bunk@stusta.de>
  153. ---------------------------
  154. What: /sys/firmware/acpi/namespace
  155. When: 2.6.21
  156. Why: The ACPI namespace is effectively the symbol list for
  157. the BIOS. The device names are completely arbitrary
  158. and have no place being exposed to user-space.
  159. For those interested in the BIOS ACPI namespace,
  160. the BIOS can be extracted and disassembled with acpidump
  161. and iasl as documented in the pmtools package here:
  162. http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
  163. Who: Len Brown <len.brown@intel.com>
  164. ---------------------------
  165. What: ACPI procfs interface
  166. When: July 2007
  167. Why: After ACPI sysfs conversion, ACPI attributes will be duplicated
  168. in sysfs and the ACPI procfs interface should be removed.
  169. Who: Zhang Rui <rui.zhang@intel.com>
  170. ---------------------------
  171. What: /proc/acpi/button
  172. When: August 2007
  173. Why: /proc/acpi/button has been replaced by events to the input layer
  174. since 2.6.20.
  175. Who: Len Brown <len.brown@intel.com>
  176. ---------------------------
  177. What: Compaq touchscreen device emulation
  178. When: Oct 2007
  179. Files: drivers/input/tsdev.c
  180. Why: The code says it was obsolete when it was written in 2001.
  181. tslib is a userspace library which does anything tsdev can do and
  182. much more besides in userspace where this code belongs. There is no
  183. longer any need for tsdev and applications should have converted to
  184. use tslib by now.
  185. The name "tsdev" is also extremely confusing and lots of people have
  186. it loaded when they don't need/use it.
  187. Who: Richard Purdie <rpurdie@rpsys.net>
  188. ---------------------------
  189. What: read_dev_chars(), read_conf_data{,_lpm}() (s390 common I/O layer)
  190. When: December 2007
  191. Why: These functions are a leftover from 2.4 times. They have several
  192. problems:
  193. - Duplication of checks that are done in the device driver's
  194. interrupt handler
  195. - common I/O layer can't do device specific error recovery
  196. - device driver can't be notified for conditions happening during
  197. execution of the function
  198. Device drivers should issue the read device characteristics and read
  199. configuration data ccws and do the appropriate error handling
  200. themselves.
  201. Who: Cornelia Huck <cornelia.huck@de.ibm.com>
  202. ---------------------------
  203. What: i2c-ixp2000, i2c-ixp4xx and scx200_i2c drivers
  204. When: September 2007
  205. Why: Obsolete. The new i2c-gpio driver replaces all hardware-specific
  206. I2C-over-GPIO drivers.
  207. Who: Jean Delvare <khali@linux-fr.org>
  208. ---------------------------
  209. What: 'time' kernel boot parameter
  210. When: January 2008
  211. Why: replaced by 'printk.time=<value>' so that printk timestamps can be
  212. enabled or disabled as needed
  213. Who: Randy Dunlap <randy.dunlap@oracle.com>
  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. ---------------------------
  248. What: The arch/ppc and include/asm-ppc directories
  249. When: Jun 2008
  250. Why: The arch/powerpc tree is the merged architecture for ppc32 and ppc64
  251. platforms. Currently there are efforts underway to port the remaining
  252. arch/ppc platforms to the merged tree. New submissions to the arch/ppc
  253. tree have been frozen with the 2.6.22 kernel release and that tree will
  254. remain in bug-fix only mode until its scheduled removal. Platforms
  255. that are not ported by June 2008 will be removed due to the lack of an
  256. interested maintainer.
  257. Who: linuxppc-dev@ozlabs.org
  258. ---------------------------
  259. What: mthca driver's MSI support
  260. When: January 2008
  261. Files: drivers/infiniband/hw/mthca/*.[ch]
  262. Why: All mthca hardware also supports MSI-X, which provides
  263. strictly more functionality than MSI. So there is no point in
  264. having both MSI-X and MSI support in the driver.
  265. Who: Roland Dreier <rolandd@cisco.com>
  266. ---------------------------