| blob | b959659c5df46414413530bd213f1e50aa528ee3 |
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: Deprecated snapshot ioctls
53 When: 2.6.36
55 Why: The ioctls in kernel/power/user.c were marked as deprecated long time
56 ago. Now they notify users about that so that they need to replace
57 their userspace. After some more time, remove them completely.
59 Who: Jiri Slaby <jirislaby@gmail.com>
61 ---------------------------
63 What: The ieee80211_regdom module parameter
64 When: March 2010 / desktop catchup
66 Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
67 and currently serves as an option for users to define an
68 ISO / IEC 3166 alpha2 code for the country they are currently
69 present in. Although there are userspace API replacements for this
70 through nl80211 distributions haven't yet caught up with implementing
71 decent alternatives through standard GUIs. Although available as an
72 option through iw or wpa_supplicant its just a matter of time before
73 distributions pick up good GUI options for this. The ideal solution
74 would actually consist of intelligent designs which would do this for
75 the user automatically even when travelling through different countries.
76 Until then we leave this module parameter as a compromise.
78 When userspace improves with reasonable widely-available alternatives for
79 this we will no longer need this module parameter. This entry hopes that
80 by the super-futuristically looking date of "March 2010" we will have
81 such replacements widely available.
83 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
85 ---------------------------
87 What: dev->power.power_state
88 When: July 2007
89 Why: Broken design for runtime control over driver power states, confusing
90 driver-internal runtime power management with: mechanisms to support
91 system-wide sleep state transitions; event codes that distinguish
92 different phases of swsusp "sleep" transitions; and userspace policy
93 inputs. This framework was never widely used, and most attempts to
94 use it were broken. Drivers should instead be exposing domain-specific
95 interfaces either to kernel or to userspace.
96 Who: Pavel Machek <pavel@ucw.cz>
98 ---------------------------
100 What: Video4Linux obsolete drivers using V4L1 API
101 When: kernel 2.6.39
102 Files: drivers/staging/se401/* drivers/staging/usbvideo/*
103 Check: drivers/staging/se401/se401.c drivers/staging/usbvideo/usbvideo.c
104 Why: There are some drivers still using V4L1 API, despite all efforts we've done
105 to migrate. Those drivers are for obsolete hardware that the old maintainer
106 didn't care (or not have the hardware anymore), and that no other developer
107 could find any hardware to buy. They probably have no practical usage today,
108 and people with such old hardware could probably keep using an older version
109 of the kernel. Those drivers will be moved to staging on 2.6.38 and, if nobody
110 cares enough to port and test them with V4L2 API, they'll be removed on 2.6.39.
111 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
113 ---------------------------
115 What: Video4Linux: Remove obsolete ioctl's
116 When: kernel 2.6.39
117 Files: include/media/videodev2.h
118 Why: Some ioctl's were defined wrong on 2.6.2 and 2.6.6, using the wrong
119 type of R/W arguments. They were fixed, but the old ioctl names are
120 still there, maintained to avoid breaking binary compatibility:
121 #define VIDIOC_OVERLAY_OLD _IOWR('V', 14, int)
122 #define VIDIOC_S_PARM_OLD _IOW('V', 22, struct v4l2_streamparm)
123 #define VIDIOC_S_CTRL_OLD _IOW('V', 28, struct v4l2_control)
124 #define VIDIOC_G_AUDIO_OLD _IOWR('V', 33, struct v4l2_audio)
125 #define VIDIOC_G_AUDOUT_OLD _IOWR('V', 49, struct v4l2_audioout)
126 #define VIDIOC_CROPCAP_OLD _IOR('V', 58, struct v4l2_cropcap)
127 There's no sense on preserving those forever, as it is very doubtful
128 that someone would try to use a such old binary with a modern kernel.
129 Removing them will allow us to remove some magic done at the V4L ioctl
130 handler.
132 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
134 ---------------------------
136 What: sys_sysctl
137 When: September 2010
138 Option: CONFIG_SYSCTL_SYSCALL
139 Why: The same information is available in a more convenient from
140 /proc/sys, and none of the sysctl variables appear to be
141 important performance wise.
143 Binary sysctls are a long standing source of subtle kernel
144 bugs and security issues.
146 When I looked several months ago all I could find after
147 searching several distributions were 5 user space programs and
148 glibc (which falls back to /proc/sys) using this syscall.
150 The man page for sysctl(2) documents it as unusable for user
151 space programs.
153 sysctl(2) is not generally ABI compatible to a 32bit user
154 space application on a 64bit and a 32bit kernel.
156 For the last several months the policy has been no new binary
157 sysctls and no one has put forward an argument to use them.
159 Binary sysctls issues seem to keep happening appearing so
160 properly deprecating them (with a warning to user space) and a
161 2 year grace warning period will mean eventually we can kill
162 them and end the pain.
164 In the mean time individual binary sysctls can be dealt with
165 in a piecewise fashion.
167 Who: Eric Biederman <ebiederm@xmission.com>
169 ---------------------------
171 What: /proc/<pid>/oom_adj
172 When: August 2012
173 Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's
174 badness heuristic used to determine which task to kill when the kernel
175 is out of memory.
177 The badness heuristic has since been rewritten since the introduction of
178 this tunable such that its meaning is deprecated. The value was
179 implemented as a bitshift on a score generated by the badness()
180 function that did not have any precise units of measure. With the
181 rewrite, the score is given as a proportion of available memory to the
182 task allocating pages, so using a bitshift which grows the score
183 exponentially is, thus, impossible to tune with fine granularity.
185 A much more powerful interface, /proc/<pid>/oom_score_adj, was
186 introduced with the oom killer rewrite that allows users to increase or
187 decrease the badness() score linearly. This interface will replace
188 /proc/<pid>/oom_adj.
190 A warning will be emitted to the kernel log if an application uses this
191 deprecated interface. After it is printed once, future warnings will be
192 suppressed until the kernel is rebooted.
194 ---------------------------
196 What: CS5535/CS5536 obsolete GPIO driver
197 When: June 2011
198 Files: drivers/staging/cs5535_gpio/*
199 Check: drivers/staging/cs5535_gpio/cs5535_gpio.c
200 Why: A newer driver replaces this; it is drivers/gpio/cs5535-gpio.c, and
201 integrates with the Linux GPIO subsystem. The old driver has been
202 moved to staging, and will be removed altogether around 2.6.40.
203 Please test the new driver, and ensure that the functionality you
204 need and any bugfixes from the old driver are available in the new
205 one.
206 Who: Andres Salomon <dilinger@queued.net>
208 --------------------------
210 What: remove EXPORT_SYMBOL(kernel_thread)
211 When: August 2006
212 Files: arch/*/kernel/*_ksyms.c
213 Check: kernel_thread
214 Why: kernel_thread is a low-level implementation detail. Drivers should
215 use the <linux/kthread.h> API instead which shields them from
216 implementation details and provides a higherlevel interface that
217 prevents bugs and code duplication
218 Who: Christoph Hellwig <hch@lst.de>
220 ---------------------------
222 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
223 (temporary transition config option provided until then)
224 The transition config option will also be removed at the same time.
225 When: before 2.6.19
226 Why: Unused symbols are both increasing the size of the kernel binary
227 and are often a sign of "wrong API"
228 Who: Arjan van de Ven <arjan@linux.intel.com>
230 ---------------------------
232 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
233 When: October 2008
234 Why: The stacking of class devices makes these values misleading and
235 inconsistent.
236 Class devices should not carry any of these properties, and bus
237 devices have SUBSYTEM and DRIVER as a replacement.
238 Who: Kay Sievers <kay.sievers@suse.de>
240 ---------------------------
242 What: ACPI procfs interface
243 When: July 2008
244 Why: ACPI sysfs conversion should be finished by January 2008.
245 ACPI procfs interface will be removed in July 2008 so that
246 there is enough time for the user space to catch up.
247 Who: Zhang Rui <rui.zhang@intel.com>
249 ---------------------------
251 What: CONFIG_ACPI_PROCFS_POWER
252 When: 2.6.39
253 Why: sysfs I/F for ACPI power devices, including AC and Battery,
254 has been working in upstream kenrel since 2.6.24, Sep 2007.
255 In 2.6.37, we make the sysfs I/F always built in and this option
256 disabled by default.
257 Remove this option and the ACPI power procfs interface in 2.6.39.
258 Who: Zhang Rui <rui.zhang@intel.com>
260 ---------------------------
262 What: /proc/acpi/button
263 When: August 2007
264 Why: /proc/acpi/button has been replaced by events to the input layer
265 since 2.6.20.
266 Who: Len Brown <len.brown@intel.com>
268 ---------------------------
270 What: /proc/acpi/event
271 When: February 2008
272 Why: /proc/acpi/event has been replaced by events via the input layer
273 and netlink since 2.6.23.
274 Who: Len Brown <len.brown@intel.com>
276 ---------------------------
278 What: i386/x86_64 bzImage symlinks
279 When: April 2010
281 Why: The i386/x86_64 merge provides a symlink to the old bzImage
282 location so not yet updated user space tools, e.g. package
283 scripts, do not break.
284 Who: Thomas Gleixner <tglx@linutronix.de>
286 ---------------------------
288 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
289 When: February 2010
290 Why: All callers should use explicit gpio_request()/gpio_free().
291 The autorequest mechanism in gpiolib was provided mostly as a
292 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
293 Those users have now largely migrated. Platforms implementing
294 the GPIO interfaces without using gpiolib will see no changes.
295 Who: David Brownell <dbrownell@users.sourceforge.net>
296 ---------------------------
298 What: b43 support for firmware revision < 410
299 When: The schedule was July 2008, but it was decided that we are going to keep the
300 code as long as there are no major maintanance headaches.
301 So it _could_ be removed _any_ time now, if it conflicts with something new.
302 Why: The support code for the old firmware hurts code readability/maintainability
303 and slightly hurts runtime performance. Bugfixes for the old firmware
304 are not provided by Broadcom anymore.
305 Who: Michael Buesch <mb@bu3sch.de>
307 ---------------------------
309 What: /sys/o2cb symlink
310 When: January 2010
311 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
312 exists as a symlink for backwards compatibility for old versions of
313 ocfs2-tools. 2 years should be sufficient time to phase in new versions
314 which know to look in /sys/fs/o2cb.
315 Who: ocfs2-devel@oss.oracle.com
317 ---------------------------
319 What: Ability for non root users to shm_get hugetlb pages based on mlock
320 resource limits
321 When: 2.6.31
322 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
323 have CAP_IPC_LOCK to be able to allocate shm segments backed by
324 huge pages. The mlock based rlimit check to allow shm hugetlb is
325 inconsistent with mmap based allocations. Hence it is being
326 deprecated.
327 Who: Ravikiran Thirumalai <kiran@scalex86.org>
329 ---------------------------
331 What: CONFIG_THERMAL_HWMON
332 When: January 2009
333 Why: This option was introduced just to allow older lm-sensors userspace
334 to keep working over the upgrade to 2.6.26. At the scheduled time of
335 removal fixed lm-sensors (2.x or 3.x) should be readily available.
336 Who: Rene Herman <rene.herman@gmail.com>
338 ---------------------------
340 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
341 (in net/core/net-sysfs.c)
342 When: After the only user (hal) has seen a release with the patches
343 for enough time, probably some time in 2010.
344 Why: Over 1K .text/.data size reduction, data is available in other
345 ways (ioctls)
346 Who: Johannes Berg <johannes@sipsolutions.net>
348 ---------------------------
350 What: sysfs ui for changing p4-clockmod parameters
351 When: September 2009
352 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
353 e088e4c9cdb618675874becb91b2fd581ee707e6.
354 Removal is subject to fixing any remaining bugs in ACPI which may
355 cause the thermal throttling not to happen at the right time.
356 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
358 -----------------------------
360 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
361 When: 2011
362 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
363 represent a machine's physical PCI slots. The change in semantics
364 had userspace implications, as the hotplug core no longer allowed
365 drivers to create multiple sysfs files per physical slot (required
366 for multi-function devices, e.g.). fakephp was seen as a developer's
367 tool only, and its interface changed. Too late, we learned that
368 there were some users of the fakephp interface.
370 In 2.6.30, the original fakephp interface was restored. At the same
371 time, the PCI core gained the ability that fakephp provided, namely
372 function-level hot-remove and hot-add.
374 Since the PCI core now provides the same functionality, exposed in:
376 /sys/bus/pci/rescan
377 /sys/bus/pci/devices/.../remove
378 /sys/bus/pci/devices/.../rescan
380 there is no functional reason to maintain fakephp as well.
382 We will keep the existing module so that 'modprobe fakephp' will
383 present the old /sys/bus/pci/slots/... interface for compatibility,
384 but users are urged to migrate their applications to the API above.
386 After a reasonable transition period, we will remove the legacy
387 fakephp interface.
388 Who: Alex Chiang <achiang@hp.com>
390 ---------------------------
392 What: CONFIG_RFKILL_INPUT
393 When: 2.6.33
394 Why: Should be implemented in userspace, policy daemon.
395 Who: Johannes Berg <johannes@sipsolutions.net>
397 ----------------------------
399 What: sound-slot/service-* module aliases and related clutters in
400 sound/sound_core.c
401 When: August 2010
402 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
403 (14) and requests modules using custom sound-slot/service-*
404 module aliases. The only benefit of doing this is allowing
405 use of custom module aliases which might as well be considered
406 a bug at this point. This preemptive claiming prevents
407 alternative OSS implementations.
409 Till the feature is removed, the kernel will be requesting
410 both sound-slot/service-* and the standard char-major-* module
411 aliases and allow turning off the pre-claiming selectively via
412 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
413 kernel parameter.
415 After the transition phase is complete, both the custom module
416 aliases and switches to disable it will go away. This removal
417 will also allow making ALSA OSS emulation independent of
418 sound_core. The dependency will be broken then too.
419 Who: Tejun Heo <tj@kernel.org>
421 ----------------------------
423 What: Support for lcd_switch and display_get in asus-laptop driver
424 When: March 2010
425 Why: These two features use non-standard interfaces. There are the
426 only features that really need multiple path to guess what's
427 the right method name on a specific laptop.
429 Removing them will allow to remove a lot of code an significantly
430 clean the drivers.
432 This will affect the backlight code which won't be able to know
433 if the backlight is on or off. The platform display file will also be
434 write only (like the one in eeepc-laptop).
436 This should'nt affect a lot of user because they usually know
437 when their display is on or off.
439 Who: Corentin Chary <corentin.chary@gmail.com>
441 ----------------------------
443 What: sysfs-class-rfkill state file
444 When: Feb 2014
445 Files: net/rfkill/core.c
446 Why: Documented as obsolete since Feb 2010. This file is limited to 3
447 states while the rfkill drivers can have 4 states.
448 Who: anybody or Florian Mickler <florian@mickler.org>
450 ----------------------------
452 What: sysfs-class-rfkill claim file
453 When: Feb 2012
454 Files: net/rfkill/core.c
455 Why: It is not possible to claim an rfkill driver since 2007. This is
456 Documented as obsolete since Feb 2010.
457 Who: anybody or Florian Mickler <florian@mickler.org>
459 ----------------------------
461 What: capifs
462 When: February 2011
463 Files: drivers/isdn/capi/capifs.*
464 Why: udev fully replaces this special file system that only contains CAPI
465 NCCI TTY device nodes. User space (pppdcapiplugin) works without
466 noticing the difference.
467 Who: Jan Kiszka <jan.kiszka@web.de>
469 ----------------------------
471 What: KVM paravirt mmu host support
472 When: January 2011
473 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
474 on newer and older hardware. It is already not exposed to the guest,
475 and kept only for live migration purposes.
476 Who: Avi Kivity <avi@redhat.com>
478 ----------------------------
480 What: iwlwifi 50XX module parameters
481 When: 2.6.40
482 Why: The "..50" modules parameters were used to configure 5000 series and
483 up devices; different set of module parameters also available for 4965
484 with same functionalities. Consolidate both set into single place
485 in drivers/net/wireless/iwlwifi/iwl-agn.c
487 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
489 ----------------------------
491 What: iwl4965 alias support
492 When: 2.6.40
493 Why: Internal alias support has been present in module-init-tools for some
494 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
495 with no impact.
497 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
499 ---------------------------
501 What: xt_NOTRACK
502 Files: net/netfilter/xt_NOTRACK.c
503 When: April 2011
504 Why: Superseded by xt_CT
505 Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
507 ----------------------------
509 What: IRQF_DISABLED
510 When: 2.6.36
511 Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled
512 Who: Thomas Gleixner <tglx@linutronix.de>
514 ----------------------------
516 What: The acpi_sleep=s4_nonvs command line option
517 When: 2.6.37
518 Files: arch/x86/kernel/acpi/sleep.c
519 Why: superseded by acpi_sleep=nonvs
520 Who: Rafael J. Wysocki <rjw@sisk.pl>
522 ----------------------------
524 What: PCI DMA unmap state API
525 When: August 2012
526 Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
527 with DMA unmap state API (DMA unmap state API can be used for
528 any bus).
529 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
531 ----------------------------
533 What: DMA_xxBIT_MASK macros
534 When: Jun 2011
535 Why: DMA_xxBIT_MASK macros were replaced with DMA_BIT_MASK() macros.
536 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
538 ----------------------------
540 What: namespace cgroup (ns_cgroup)
541 When: 2.6.38
542 Why: The ns_cgroup leads to some problems:
543 * cgroup creation is out-of-control
544 * cgroup name can conflict when pids are looping
545 * it is not possible to have a single process handling
546 a lot of namespaces without falling in a exponential creation time
547 * we may want to create a namespace without creating a cgroup
549 The ns_cgroup is replaced by a compatibility flag 'clone_children',
550 where a newly created cgroup will copy the parent cgroup values.
551 The userspace has to manually create a cgroup and add a task to
552 the 'tasks' file.
553 Who: Daniel Lezcano <daniel.lezcano@free.fr>
555 ----------------------------
557 What: iwlwifi disable_hw_scan module parameters
558 When: 2.6.40
559 Why: Hareware scan is the prefer method for iwlwifi devices for
560 scanning operation. Remove software scan support for all the
561 iwlwifi devices.
563 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
565 ----------------------------
567 What: access to nfsd auth cache through sys_nfsservctl or '.' files
568 in the 'nfsd' filesystem.
569 When: 2.6.40
570 Why: This is a legacy interface which have been replaced by a more
571 dynamic cache. Continuing to maintain this interface is an
572 unnecessary burden.
573 Who: NeilBrown <neilb@suse.de>
575 ----------------------------
577 What: i2c_adapter.id
578 When: June 2011
579 Why: This field is deprecated. I2C device drivers shouldn't change their
580 behavior based on the underlying I2C adapter. Instead, the I2C
581 adapter driver should instantiate the I2C devices and provide the
582 needed platform-specific information.
583 Who: Jean Delvare <khali@linux-fr.org>
585 ----------------------------
587 What: cancel_rearming_delayed_work[queue]()
588 When: 2.6.39
590 Why: The functions have been superceded by cancel_delayed_work_sync()
591 quite some time ago. The conversion is trivial and there is no
592 in-kernel user left.
593 Who: Tejun Heo <tj@kernel.org>
595 ----------------------------
597 What: Legacy, non-standard chassis intrusion detection interface.
598 When: June 2011
599 Why: The adm9240, w83792d and w83793 hardware monitoring drivers have
600 legacy interfaces for chassis intrusion detection. A standard
601 interface has been added to each driver, so the legacy interface
602 can be removed.
603 Who: Jean Delvare <khali@linux-fr.org>
605 ----------------------------