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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.
7 ---------------------------
9 What: PRISM54
10 When: 2.6.34
12 Why: prism54 FullMAC PCI / Cardbus devices used to be supported only by the
13 prism54 wireless driver. After Intersil stopped selling these
14 devices in preference for the newer more flexible SoftMAC devices
15 a SoftMAC device driver was required and prism54 did not support
16 them. The p54pci driver now exists and has been present in the kernel for
17 a while. This driver supports both SoftMAC devices and FullMAC devices.
18 The main difference between these devices was the amount of memory which
19 could be used for the firmware. The SoftMAC devices support a smaller
20 amount of memory. Because of this the SoftMAC firmware fits into FullMAC
21 devices's memory. p54pci supports not only PCI / Cardbus but also USB
22 and SPI. Since p54pci supports all devices prism54 supports
23 you will have a conflict. I'm not quite sure how distributions are
24 handling this conflict right now. prism54 was kept around due to
25 claims users may experience issues when using the SoftMAC driver.
26 Time has passed users have not reported issues. If you use prism54
27 and for whatever reason you cannot use p54pci please let us know!
28 E-mail us at: linux-wireless@vger.kernel.org
30 For more information see the p54 wiki page:
32 http://wireless.kernel.org/en/users/Drivers/p54
34 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
36 ---------------------------
38 What: IRQF_SAMPLE_RANDOM
39 Check: IRQF_SAMPLE_RANDOM
40 When: July 2009
42 Why: Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy
43 sources in the kernel's current entropy model. To resolve this, every
44 input point to the kernel's entropy pool needs to better document the
45 type of entropy source it actually is. This will be replaced with
46 additional add_*_randomness functions in drivers/char/random.c
48 Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com>
50 ---------------------------
52 What: The ieee80211_regdom module parameter
53 When: March 2010 / desktop catchup
55 Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
56 and currently serves as an option for users to define an
57 ISO / IEC 3166 alpha2 code for the country they are currently
58 present in. Although there are userspace API replacements for this
59 through nl80211 distributions haven't yet caught up with implementing
60 decent alternatives through standard GUIs. Although available as an
61 option through iw or wpa_supplicant its just a matter of time before
62 distributions pick up good GUI options for this. The ideal solution
63 would actually consist of intelligent designs which would do this for
64 the user automatically even when travelling through different countries.
65 Until then we leave this module parameter as a compromise.
67 When userspace improves with reasonable widely-available alternatives for
68 this we will no longer need this module parameter. This entry hopes that
69 by the super-futuristically looking date of "March 2010" we will have
70 such replacements widely available.
72 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
74 ---------------------------
76 What: CONFIG_WIRELESS_OLD_REGULATORY - old static regulatory information
77 When: March 2010 / desktop catchup
79 Why: The old regulatory infrastructure has been replaced with a new one
80 which does not require statically defined regulatory domains. We do
81 not want to keep static regulatory domains in the kernel due to the
82 the dynamic nature of regulatory law and localization. We kept around
83 the old static definitions for the regulatory domains of:
85 * US
86 * JP
87 * EU
89 and used by default the US when CONFIG_WIRELESS_OLD_REGULATORY was
90 set. We will remove this option once the standard Linux desktop catches
91 up with the new userspace APIs we have implemented.
93 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
95 ---------------------------
97 What: dev->power.power_state
98 When: July 2007
99 Why: Broken design for runtime control over driver power states, confusing
100 driver-internal runtime power management with: mechanisms to support
101 system-wide sleep state transitions; event codes that distinguish
102 different phases of swsusp "sleep" transitions; and userspace policy
103 inputs. This framework was never widely used, and most attempts to
104 use it were broken. Drivers should instead be exposing domain-specific
105 interfaces either to kernel or to userspace.
106 Who: Pavel Machek <pavel@suse.cz>
108 ---------------------------
110 What: Video4Linux API 1 ioctls and from Video devices.
111 When: July 2009
112 Files: include/linux/videodev.h
113 Check: include/linux/videodev.h
114 Why: V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
115 series. The old API have lots of drawbacks and don't provide enough
116 means to work with all video and audio standards. The newer API is
117 already available on the main drivers and should be used instead.
118 Newer drivers should use v4l_compat_translate_ioctl function to handle
119 old calls, replacing to newer ones.
120 Decoder iocts are using internally to allow video drivers to
121 communicate with video decoders. This should also be improved to allow
122 V4L2 calls being translated into compatible internal ioctls.
123 Compatibility ioctls will be provided, for a while, via
124 v4l1-compat module.
125 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
127 ---------------------------
129 What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
130 When: November 2005
131 Files: drivers/pcmcia/: pcmcia_ioctl.c
132 Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
133 normal hotpluggable bus, and with it using the default kernel
134 infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
135 control ioctl needed by cardmgr and cardctl from pcmcia-cs is
136 unnecessary, and makes further cleanups and integration of the
137 PCMCIA subsystem into the Linux kernel device driver model more
138 difficult. The features provided by cardmgr and cardctl are either
139 handled by the kernel itself now or are available in the new
140 pcmciautils package available at
141 http://kernel.org/pub/linux/utils/kernel/pcmcia/
142 Who: Dominik Brodowski <linux@brodo.de>
144 ---------------------------
146 What: sys_sysctl
147 When: September 2010
148 Option: CONFIG_SYSCTL_SYSCALL
149 Why: The same information is available in a more convenient from
150 /proc/sys, and none of the sysctl variables appear to be
151 important performance wise.
153 Binary sysctls are a long standing source of subtle kernel
154 bugs and security issues.
156 When I looked several months ago all I could find after
157 searching several distributions were 5 user space programs and
158 glibc (which falls back to /proc/sys) using this syscall.
160 The man page for sysctl(2) documents it as unusable for user
161 space programs.
163 sysctl(2) is not generally ABI compatible to a 32bit user
164 space application on a 64bit and a 32bit kernel.
166 For the last several months the policy has been no new binary
167 sysctls and no one has put forward an argument to use them.
169 Binary sysctls issues seem to keep happening appearing so
170 properly deprecating them (with a warning to user space) and a
171 2 year grace warning period will mean eventually we can kill
172 them and end the pain.
174 In the mean time individual binary sysctls can be dealt with
175 in a piecewise fashion.
177 Who: Eric Biederman <ebiederm@xmission.com>
179 ---------------------------
181 What: remove EXPORT_SYMBOL(kernel_thread)
182 When: August 2006
183 Files: arch/*/kernel/*_ksyms.c
184 Check: kernel_thread
185 Why: kernel_thread is a low-level implementation detail. Drivers should
186 use the <linux/kthread.h> API instead which shields them from
187 implementation details and provides a higherlevel interface that
188 prevents bugs and code duplication
189 Who: Christoph Hellwig <hch@lst.de>
191 ---------------------------
193 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
194 (temporary transition config option provided until then)
195 The transition config option will also be removed at the same time.
196 When: before 2.6.19
197 Why: Unused symbols are both increasing the size of the kernel binary
198 and are often a sign of "wrong API"
199 Who: Arjan van de Ven <arjan@linux.intel.com>
201 ---------------------------
203 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
204 When: October 2008
205 Why: The stacking of class devices makes these values misleading and
206 inconsistent.
207 Class devices should not carry any of these properties, and bus
208 devices have SUBSYTEM and DRIVER as a replacement.
209 Who: Kay Sievers <kay.sievers@suse.de>
211 ---------------------------
213 What: ACPI procfs interface
214 When: July 2008
215 Why: ACPI sysfs conversion should be finished by January 2008.
216 ACPI procfs interface will be removed in July 2008 so that
217 there is enough time for the user space to catch up.
218 Who: Zhang Rui <rui.zhang@intel.com>
220 ---------------------------
222 What: /proc/acpi/button
223 When: August 2007
224 Why: /proc/acpi/button has been replaced by events to the input layer
225 since 2.6.20.
226 Who: Len Brown <len.brown@intel.com>
228 ---------------------------
230 What: /proc/acpi/event
231 When: February 2008
232 Why: /proc/acpi/event has been replaced by events via the input layer
233 and netlink since 2.6.23.
234 Who: Len Brown <len.brown@intel.com>
236 ---------------------------
238 What: i386/x86_64 bzImage symlinks
239 When: April 2010
241 Why: The i386/x86_64 merge provides a symlink to the old bzImage
242 location so not yet updated user space tools, e.g. package
243 scripts, do not break.
244 Who: Thomas Gleixner <tglx@linutronix.de>
246 ---------------------------
248 What (Why):
249 - xt_recent: the old ipt_recent proc dir
250 (superseded by /proc/net/xt_recent)
252 When: January 2009 or Linux 2.7.0, whichever comes first
253 Why: Superseded by newer revisions or modules
254 Who: Jan Engelhardt <jengelh@computergmbh.de>
256 ---------------------------
258 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
259 When: February 2010
260 Why: All callers should use explicit gpio_request()/gpio_free().
261 The autorequest mechanism in gpiolib was provided mostly as a
262 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
263 Those users have now largely migrated. Platforms implementing
264 the GPIO interfaces without using gpiolib will see no changes.
265 Who: David Brownell <dbrownell@users.sourceforge.net>
266 ---------------------------
268 What: b43 support for firmware revision < 410
269 When: The schedule was July 2008, but it was decided that we are going to keep the
270 code as long as there are no major maintanance headaches.
271 So it _could_ be removed _any_ time now, if it conflicts with something new.
272 Why: The support code for the old firmware hurts code readability/maintainability
273 and slightly hurts runtime performance. Bugfixes for the old firmware
274 are not provided by Broadcom anymore.
275 Who: Michael Buesch <mb@bu3sch.de>
277 ---------------------------
279 What: usedac i386 kernel parameter
280 When: 2.6.27
281 Why: replaced by allowdac and no dac combination
282 Who: Glauber Costa <gcosta@redhat.com>
284 ---------------------------
286 What: print_fn_descriptor_symbol()
287 When: October 2009
288 Why: The %pF vsprintf format provides the same functionality in a
289 simpler way. print_fn_descriptor_symbol() is deprecated but
290 still present to give out-of-tree modules time to change.
291 Who: Bjorn Helgaas <bjorn.helgaas@hp.com>
293 ---------------------------
295 What: /sys/o2cb symlink
296 When: January 2010
297 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
298 exists as a symlink for backwards compatibility for old versions of
299 ocfs2-tools. 2 years should be sufficient time to phase in new versions
300 which know to look in /sys/fs/o2cb.
301 Who: ocfs2-devel@oss.oracle.com
303 ---------------------------
305 What: SCTP_GET_PEER_ADDRS_NUM_OLD, SCTP_GET_PEER_ADDRS_OLD,
306 SCTP_GET_LOCAL_ADDRS_NUM_OLD, SCTP_GET_LOCAL_ADDRS_OLD
307 When: June 2009
308 Why: A newer version of the options have been introduced in 2005 that
309 removes the limitions of the old API. The sctp library has been
310 converted to use these new options at the same time. Any user
311 space app that directly uses the old options should convert to using
312 the new options.
313 Who: Vlad Yasevich <vladislav.yasevich@hp.com>
315 ---------------------------
317 What: Ability for non root users to shm_get hugetlb pages based on mlock
318 resource limits
319 When: 2.6.31
320 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
321 have CAP_IPC_LOCK to be able to allocate shm segments backed by
322 huge pages. The mlock based rlimit check to allow shm hugetlb is
323 inconsistent with mmap based allocations. Hence it is being
324 deprecated.
325 Who: Ravikiran Thirumalai <kiran@scalex86.org>
327 ---------------------------
329 What: CONFIG_THERMAL_HWMON
330 When: January 2009
331 Why: This option was introduced just to allow older lm-sensors userspace
332 to keep working over the upgrade to 2.6.26. At the scheduled time of
333 removal fixed lm-sensors (2.x or 3.x) should be readily available.
334 Who: Rene Herman <rene.herman@gmail.com>
336 ---------------------------
338 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
339 (in net/core/net-sysfs.c)
340 When: After the only user (hal) has seen a release with the patches
341 for enough time, probably some time in 2010.
342 Why: Over 1K .text/.data size reduction, data is available in other
343 ways (ioctls)
344 Who: Johannes Berg <johannes@sipsolutions.net>
346 ---------------------------
348 What: CONFIG_NF_CT_ACCT
349 When: 2.6.29
350 Why: Accounting can now be enabled/disabled without kernel recompilation.
351 Currently used only to set a default value for a feature that is also
352 controlled by a kernel/module/sysfs/sysctl parameter.
353 Who: Krzysztof Piotr Oledzki <ole@ans.pl>
355 ---------------------------
357 What: sysfs ui for changing p4-clockmod parameters
358 When: September 2009
359 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
360 e088e4c9cdb618675874becb91b2fd581ee707e6.
361 Removal is subject to fixing any remaining bugs in ACPI which may
362 cause the thermal throttling not to happen at the right time.
363 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
365 -----------------------------
367 What: __do_IRQ all in one fits nothing interrupt handler
368 When: 2.6.32
369 Why: __do_IRQ was kept for easy migration to the type flow handlers.
370 More than two years of migration time is enough.
371 Who: Thomas Gleixner <tglx@linutronix.de>
373 -----------------------------
375 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
376 When: 2011
377 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
378 represent a machine's physical PCI slots. The change in semantics
379 had userspace implications, as the hotplug core no longer allowed
380 drivers to create multiple sysfs files per physical slot (required
381 for multi-function devices, e.g.). fakephp was seen as a developer's
382 tool only, and its interface changed. Too late, we learned that
383 there were some users of the fakephp interface.
385 In 2.6.30, the original fakephp interface was restored. At the same
386 time, the PCI core gained the ability that fakephp provided, namely
387 function-level hot-remove and hot-add.
389 Since the PCI core now provides the same functionality, exposed in:
391 /sys/bus/pci/rescan
392 /sys/bus/pci/devices/.../remove
393 /sys/bus/pci/devices/.../rescan
395 there is no functional reason to maintain fakephp as well.
397 We will keep the existing module so that 'modprobe fakephp' will
398 present the old /sys/bus/pci/slots/... interface for compatibility,
399 but users are urged to migrate their applications to the API above.
401 After a reasonable transition period, we will remove the legacy
402 fakephp interface.
403 Who: Alex Chiang <achiang@hp.com>
405 ---------------------------
407 What: i2c-voodoo3 driver
408 When: October 2009
409 Why: Superseded by tdfxfb. I2C/DDC support used to live in a separate
410 driver but this caused driver conflicts.
411 Who: Jean Delvare <khali@linux-fr.org>
412 Krzysztof Helt <krzysztof.h1@wp.pl>
414 ---------------------------
416 What: CONFIG_RFKILL_INPUT
417 When: 2.6.33
418 Why: Should be implemented in userspace, policy daemon.
419 Who: Johannes Berg <johannes@sipsolutions.net>
421 ----------------------------
423 What: lock_policy_rwsem_* and unlock_policy_rwsem_* will not be
424 exported interface anymore.
425 When: 2.6.33
426 Why: cpu_policy_rwsem has a new cleaner definition making it local to
427 cpufreq core and contained inside cpufreq.c. Other dependent
428 drivers should not use it in order to safely avoid lockdep issues.
429 Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
431 ----------------------------
433 What: sound-slot/service-* module aliases and related clutters in
434 sound/sound_core.c
435 When: August 2010
436 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
437 (14) and requests modules using custom sound-slot/service-*
438 module aliases. The only benefit of doing this is allowing
439 use of custom module aliases which might as well be considered
440 a bug at this point. This preemptive claiming prevents
441 alternative OSS implementations.
443 Till the feature is removed, the kernel will be requesting
444 both sound-slot/service-* and the standard char-major-* module
445 aliases and allow turning off the pre-claiming selectively via
446 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
447 kernel parameter.
449 After the transition phase is complete, both the custom module
450 aliases and switches to disable it will go away. This removal
451 will also allow making ALSA OSS emulation independent of
452 sound_core. The dependency will be broken then too.
453 Who: Tejun Heo <tj@kernel.org>