Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...
[deliverable/linux.git] / Documentation / feature-removal-schedule.txt
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 ---------------------------
8
9 What: old static regulatory information and ieee80211_regdom module parameter
10 When: 2.6.29
11 Why: The old regulatory infrastructure has been replaced with a new one
12 which does not require statically defined regulatory domains. We do
13 not want to keep static regulatory domains in the kernel due to the
14 the dynamic nature of regulatory law and localization. We kept around
15 the old static definitions for the regulatory domains of:
16 * US
17 * JP
18 * EU
19 and used by default the US when CONFIG_WIRELESS_OLD_REGULATORY was
20 set. We also kept around the ieee80211_regdom module parameter in case
21 some applications were relying on it. Changing regulatory domains
22 can now be done instead by using nl80211, as is done with iw.
23 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
24
25 ---------------------------
26
27 What: dev->power.power_state
28 When: July 2007
29 Why: Broken design for runtime control over driver power states, confusing
30 driver-internal runtime power management with: mechanisms to support
31 system-wide sleep state transitions; event codes that distinguish
32 different phases of swsusp "sleep" transitions; and userspace policy
33 inputs. This framework was never widely used, and most attempts to
34 use it were broken. Drivers should instead be exposing domain-specific
35 interfaces either to kernel or to userspace.
36 Who: Pavel Machek <pavel@suse.cz>
37
38 ---------------------------
39
40 What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
41 When: December 2008
42 Files: include/linux/video_decoder.h include/linux/videodev.h
43 Check: include/linux/video_decoder.h include/linux/videodev.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 Compatibility ioctls will be provided, for a while, via
54 v4l1-compat module.
55 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
56
57 ---------------------------
58
59 What: old tuner-3036 i2c driver
60 When: 2.6.28
61 Why: This driver is for VERY old i2c-over-parallel port teletext receiver
62 boxes. Rather then spending effort on converting this driver to V4L2,
63 and since it is extremely unlikely that anyone still uses one of these
64 devices, it was decided to drop it.
65 Who: Hans Verkuil <hverkuil@xs4all.nl>
66 Mauro Carvalho Chehab <mchehab@infradead.org>
67
68 ---------------------------
69
70 What: V4L2 dpc7146 driver
71 When: 2.6.28
72 Why: Old driver for the dpc7146 demonstration board that is no longer
73 relevant. The last time this was tested on actual hardware was
74 probably around 2002. Since this is a driver for a demonstration
75 board the decision was made to remove it rather than spending a
76 lot of effort continually updating this driver to stay in sync
77 with the latest internal V4L2 or I2C API.
78 Who: Hans Verkuil <hverkuil@xs4all.nl>
79 Mauro Carvalho Chehab <mchehab@infradead.org>
80
81 ---------------------------
82
83 What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
84 When: November 2005
85 Files: drivers/pcmcia/: pcmcia_ioctl.c
86 Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
87 normal hotpluggable bus, and with it using the default kernel
88 infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
89 control ioctl needed by cardmgr and cardctl from pcmcia-cs is
90 unnecessary, and makes further cleanups and integration of the
91 PCMCIA subsystem into the Linux kernel device driver model more
92 difficult. The features provided by cardmgr and cardctl are either
93 handled by the kernel itself now or are available in the new
94 pcmciautils package available at
95 http://kernel.org/pub/linux/utils/kernel/pcmcia/
96 Who: Dominik Brodowski <linux@brodo.de>
97
98 ---------------------------
99
100 What: sys_sysctl
101 When: September 2010
102 Option: CONFIG_SYSCTL_SYSCALL
103 Why: The same information is available in a more convenient from
104 /proc/sys, and none of the sysctl variables appear to be
105 important performance wise.
106
107 Binary sysctls are a long standing source of subtle kernel
108 bugs and security issues.
109
110 When I looked several months ago all I could find after
111 searching several distributions were 5 user space programs and
112 glibc (which falls back to /proc/sys) using this syscall.
113
114 The man page for sysctl(2) documents it as unusable for user
115 space programs.
116
117 sysctl(2) is not generally ABI compatible to a 32bit user
118 space application on a 64bit and a 32bit kernel.
119
120 For the last several months the policy has been no new binary
121 sysctls and no one has put forward an argument to use them.
122
123 Binary sysctls issues seem to keep happening appearing so
124 properly deprecating them (with a warning to user space) and a
125 2 year grace warning period will mean eventually we can kill
126 them and end the pain.
127
128 In the mean time individual binary sysctls can be dealt with
129 in a piecewise fashion.
130
131 Who: Eric Biederman <ebiederm@xmission.com>
132
133 ---------------------------
134
135 What: remove EXPORT_SYMBOL(kernel_thread)
136 When: August 2006
137 Files: arch/*/kernel/*_ksyms.c
138 Check: kernel_thread
139 Why: kernel_thread is a low-level implementation detail. Drivers should
140 use the <linux/kthread.h> API instead which shields them from
141 implementation details and provides a higherlevel interface that
142 prevents bugs and code duplication
143 Who: Christoph Hellwig <hch@lst.de>
144
145 ---------------------------
146
147 What: eepro100 network driver
148 When: January 2007
149 Why: replaced by the e100 driver
150 Who: Adrian Bunk <bunk@stusta.de>
151
152 ---------------------------
153
154 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
155 (temporary transition config option provided until then)
156 The transition config option will also be removed at the same time.
157 When: before 2.6.19
158 Why: Unused symbols are both increasing the size of the kernel binary
159 and are often a sign of "wrong API"
160 Who: Arjan van de Ven <arjan@linux.intel.com>
161
162 ---------------------------
163
164 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
165 When: October 2008
166 Why: The stacking of class devices makes these values misleading and
167 inconsistent.
168 Class devices should not carry any of these properties, and bus
169 devices have SUBSYTEM and DRIVER as a replacement.
170 Who: Kay Sievers <kay.sievers@suse.de>
171
172 ---------------------------
173
174 What: ACPI procfs interface
175 When: July 2008
176 Why: ACPI sysfs conversion should be finished by January 2008.
177 ACPI procfs interface will be removed in July 2008 so that
178 there is enough time for the user space to catch up.
179 Who: Zhang Rui <rui.zhang@intel.com>
180
181 ---------------------------
182
183 What: /proc/acpi/button
184 When: August 2007
185 Why: /proc/acpi/button has been replaced by events to the input layer
186 since 2.6.20.
187 Who: Len Brown <len.brown@intel.com>
188
189 ---------------------------
190
191 What: /proc/acpi/event
192 When: February 2008
193 Why: /proc/acpi/event has been replaced by events via the input layer
194 and netlink since 2.6.23.
195 Who: Len Brown <len.brown@intel.com>
196
197 ---------------------------
198
199 What: libata spindown skipping and warning
200 When: Dec 2008
201 Why: Some halt(8) implementations synchronize caches for and spin
202 down libata disks because libata didn't use to spin down disk on
203 system halt (only synchronized caches).
204 Spin down on system halt is now implemented. sysfs node
205 /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
206 spin down support is available.
207 Because issuing spin down command to an already spun down disk
208 makes some disks spin up just to spin down again, libata tracks
209 device spindown status to skip the extra spindown command and
210 warn about it.
211 This is to give userspace tools the time to get updated and will
212 be removed after userspace is reasonably updated.
213 Who: Tejun Heo <htejun@gmail.com>
214
215 ---------------------------
216
217 What: i386/x86_64 bzImage symlinks
218 When: April 2010
219
220 Why: The i386/x86_64 merge provides a symlink to the old bzImage
221 location so not yet updated user space tools, e.g. package
222 scripts, do not break.
223 Who: Thomas Gleixner <tglx@linutronix.de>
224
225 ---------------------------
226
227 What (Why):
228 - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
229 (superseded by xt_TOS/xt_tos target & match)
230
231 - "forwarding" header files like ipt_mac.h in
232 include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/
233
234 - xt_CONNMARK match revision 0
235 (superseded by xt_CONNMARK match revision 1)
236
237 - xt_MARK target revisions 0 and 1
238 (superseded by xt_MARK match revision 2)
239
240 - xt_connmark match revision 0
241 (superseded by xt_connmark match revision 1)
242
243 - xt_conntrack match revision 0
244 (superseded by xt_conntrack match revision 1)
245
246 - xt_iprange match revision 0,
247 include/linux/netfilter_ipv4/ipt_iprange.h
248 (superseded by xt_iprange match revision 1)
249
250 - xt_mark match revision 0
251 (superseded by xt_mark match revision 1)
252
253 - xt_recent: the old ipt_recent proc dir
254 (superseded by /proc/net/xt_recent)
255
256 When: January 2009 or Linux 2.7.0, whichever comes first
257 Why: Superseded by newer revisions or modules
258 Who: Jan Engelhardt <jengelh@computergmbh.de>
259
260 ---------------------------
261
262 What: b43 support for firmware revision < 410
263 When: July 2008
264 Why: The support code for the old firmware hurts code readability/maintainability
265 and slightly hurts runtime performance. Bugfixes for the old firmware
266 are not provided by Broadcom anymore.
267 Who: Michael Buesch <mb@bu3sch.de>
268
269 ---------------------------
270
271 What: init_mm export
272 When: 2.6.26
273 Why: Not used in-tree. The current out-of-tree users used it to
274 work around problems in the CPA code which should be resolved
275 by now. One usecase was described to provide verification code
276 of the CPA operation. That's a good idea in general, but such
277 code / infrastructure should be in the kernel and not in some
278 out-of-tree driver.
279 Who: Thomas Gleixner <tglx@linutronix.de>
280
281 ----------------------------
282
283 What: usedac i386 kernel parameter
284 When: 2.6.27
285 Why: replaced by allowdac and no dac combination
286 Who: Glauber Costa <gcosta@redhat.com>
287
288 ---------------------------
289
290 What: remove HID compat support
291 When: 2.6.29
292 Why: needed only as a temporary solution until distros fix themselves up
293 Who: Jiri Slaby <jirislaby@gmail.com>
294
295 ---------------------------
296
297 What: print_fn_descriptor_symbol()
298 When: October 2009
299 Why: The %pF vsprintf format provides the same functionality in a
300 simpler way. print_fn_descriptor_symbol() is deprecated but
301 still present to give out-of-tree modules time to change.
302 Who: Bjorn Helgaas <bjorn.helgaas@hp.com>
303
304 ---------------------------
305
306 What: /sys/o2cb symlink
307 When: January 2010
308 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
309 exists as a symlink for backwards compatibility for old versions of
310 ocfs2-tools. 2 years should be sufficient time to phase in new versions
311 which know to look in /sys/fs/o2cb.
312 Who: ocfs2-devel@oss.oracle.com
313
314 ---------------------------
315
316 What: SCTP_GET_PEER_ADDRS_NUM_OLD, SCTP_GET_PEER_ADDRS_OLD,
317 SCTP_GET_LOCAL_ADDRS_NUM_OLD, SCTP_GET_LOCAL_ADDRS_OLD
318 When: June 2009
319 Why: A newer version of the options have been introduced in 2005 that
320 removes the limitions of the old API. The sctp library has been
321 converted to use these new options at the same time. Any user
322 space app that directly uses the old options should convert to using
323 the new options.
324 Who: Vlad Yasevich <vladislav.yasevich@hp.com>
325
326 ---------------------------
327
328 What: CONFIG_THERMAL_HWMON
329 When: January 2009
330 Why: This option was introduced just to allow older lm-sensors userspace
331 to keep working over the upgrade to 2.6.26. At the scheduled time of
332 removal fixed lm-sensors (2.x or 3.x) should be readily available.
333 Who: Rene Herman <rene.herman@gmail.com>
334
335 ---------------------------
336
337 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
338 (in net/core/net-sysfs.c)
339 When: After the only user (hal) has seen a release with the patches
340 for enough time, probably some time in 2010.
341 Why: Over 1K .text/.data size reduction, data is available in other
342 ways (ioctls)
343 Who: Johannes Berg <johannes@sipsolutions.net>
344
345 ---------------------------
346
347 What: CONFIG_NF_CT_ACCT
348 When: 2.6.29
349 Why: Accounting can now be enabled/disabled without kernel recompilation.
350 Currently used only to set a default value for a feature that is also
351 controlled by a kernel/module/sysfs/sysctl parameter.
352 Who: Krzysztof Piotr Oledzki <ole@ans.pl>
353
354 ---------------------------
355
356 What: ide-scsi (BLK_DEV_IDESCSI)
357 When: 2.6.29
358 Why: The 2.6 kernel supports direct writing to ide CD drives, which
359 eliminates the need for ide-scsi. The new method is more
360 efficient in every way.
361 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
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