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 ---------------------------
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
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
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
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
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 ---------------------------
117 Option: CONFIG_SYSCTL_SYSCALL
118 Why: The same information is available in a more convenient from
119 /proc/sys, and none of the sysctl variables appear to be
120 important performance wise.
122 Binary sysctls are a long standing source of subtle kernel
123 bugs and security issues.
125 When I looked several months ago all I could find after
126 searching several distributions were 5 user space programs and
127 glibc (which falls back to /proc/sys) using this syscall.
129 The man page for sysctl(2) documents it as unusable for user
132 sysctl(2) is not generally ABI compatible to a 32bit user
133 space application on a 64bit and a 32bit kernel.
135 For the last several months the policy has been no new binary
136 sysctls and no one has put forward an argument to use them.
138 Binary sysctls issues seem to keep happening appearing so
139 properly deprecating them (with a warning to user space) and a
140 2 year grace warning period will mean eventually we can kill
141 them and end the pain.
143 In the mean time individual binary sysctls can be dealt with
144 in a piecewise fashion.
146 Who: Eric Biederman <ebiederm@xmission.com>
148 ---------------------------
150 What: /proc/<pid>/oom_adj
152 Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's
153 badness heuristic used to determine which task to kill when the kernel
156 The badness heuristic has since been rewritten since the introduction of
157 this tunable such that its meaning is deprecated. The value was
158 implemented as a bitshift on a score generated by the badness()
159 function that did not have any precise units of measure. With the
160 rewrite, the score is given as a proportion of available memory to the
161 task allocating pages, so using a bitshift which grows the score
162 exponentially is, thus, impossible to tune with fine granularity.
164 A much more powerful interface, /proc/<pid>/oom_score_adj, was
165 introduced with the oom killer rewrite that allows users to increase or
166 decrease the badness() score linearly. This interface will replace
169 A warning will be emitted to the kernel log if an application uses this
170 deprecated interface. After it is printed once, future warnings will be
171 suppressed until the kernel is rebooted.
173 ---------------------------
175 What: remove EXPORT_SYMBOL(kernel_thread)
177 Files: arch/*/kernel/*_ksyms.c
179 Why: kernel_thread is a low-level implementation detail. Drivers should
180 use the <linux/kthread.h> API instead which shields them from
181 implementation details and provides a higherlevel interface that
182 prevents bugs and code duplication
183 Who: Christoph Hellwig <hch@lst.de>
185 ---------------------------
187 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
188 (temporary transition config option provided until then)
189 The transition config option will also be removed at the same time.
191 Why: Unused symbols are both increasing the size of the kernel binary
192 and are often a sign of "wrong API"
193 Who: Arjan van de Ven <arjan@linux.intel.com>
195 ---------------------------
197 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
199 Why: The stacking of class devices makes these values misleading and
201 Class devices should not carry any of these properties, and bus
202 devices have SUBSYTEM and DRIVER as a replacement.
203 Who: Kay Sievers <kay.sievers@suse.de>
205 ---------------------------
207 What: ACPI procfs interface
209 Why: ACPI sysfs conversion should be finished by January 2008.
210 ACPI procfs interface will be removed in July 2008 so that
211 there is enough time for the user space to catch up.
212 Who: Zhang Rui <rui.zhang@intel.com>
214 ---------------------------
216 What: /proc/acpi/button
218 Why: /proc/acpi/button has been replaced by events to the input layer
220 Who: Len Brown <len.brown@intel.com>
222 ---------------------------
224 What: /proc/acpi/event
226 Why: /proc/acpi/event has been replaced by events via the input layer
227 and netlink since 2.6.23.
228 Who: Len Brown <len.brown@intel.com>
230 ---------------------------
232 What: i386/x86_64 bzImage symlinks
235 Why: The i386/x86_64 merge provides a symlink to the old bzImage
236 location so not yet updated user space tools, e.g. package
237 scripts, do not break.
238 Who: Thomas Gleixner <tglx@linutronix.de>
240 ---------------------------
242 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
244 Why: All callers should use explicit gpio_request()/gpio_free().
245 The autorequest mechanism in gpiolib was provided mostly as a
246 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
247 Those users have now largely migrated. Platforms implementing
248 the GPIO interfaces without using gpiolib will see no changes.
249 Who: David Brownell <dbrownell@users.sourceforge.net>
250 ---------------------------
252 What: b43 support for firmware revision < 410
253 When: The schedule was July 2008, but it was decided that we are going to keep the
254 code as long as there are no major maintanance headaches.
255 So it _could_ be removed _any_ time now, if it conflicts with something new.
256 Why: The support code for the old firmware hurts code readability/maintainability
257 and slightly hurts runtime performance. Bugfixes for the old firmware
258 are not provided by Broadcom anymore.
259 Who: Michael Buesch <mb@bu3sch.de>
261 ---------------------------
263 What: /sys/o2cb symlink
265 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
266 exists as a symlink for backwards compatibility for old versions of
267 ocfs2-tools. 2 years should be sufficient time to phase in new versions
268 which know to look in /sys/fs/o2cb.
269 Who: ocfs2-devel@oss.oracle.com
271 ---------------------------
273 What: Ability for non root users to shm_get hugetlb pages based on mlock
276 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
277 have CAP_IPC_LOCK to be able to allocate shm segments backed by
278 huge pages. The mlock based rlimit check to allow shm hugetlb is
279 inconsistent with mmap based allocations. Hence it is being
281 Who: Ravikiran Thirumalai <kiran@scalex86.org>
283 ---------------------------
285 What: CONFIG_THERMAL_HWMON
287 Why: This option was introduced just to allow older lm-sensors userspace
288 to keep working over the upgrade to 2.6.26. At the scheduled time of
289 removal fixed lm-sensors (2.x or 3.x) should be readily available.
290 Who: Rene Herman <rene.herman@gmail.com>
292 ---------------------------
294 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
295 (in net/core/net-sysfs.c)
296 When: After the only user (hal) has seen a release with the patches
297 for enough time, probably some time in 2010.
298 Why: Over 1K .text/.data size reduction, data is available in other
300 Who: Johannes Berg <johannes@sipsolutions.net>
302 ---------------------------
304 What: sysfs ui for changing p4-clockmod parameters
306 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
307 e088e4c9cdb618675874becb91b2fd581ee707e6.
308 Removal is subject to fixing any remaining bugs in ACPI which may
309 cause the thermal throttling not to happen at the right time.
310 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
312 -----------------------------
314 What: __do_IRQ all in one fits nothing interrupt handler
316 Why: __do_IRQ was kept for easy migration to the type flow handlers.
317 More than two years of migration time is enough.
318 Who: Thomas Gleixner <tglx@linutronix.de>
320 -----------------------------
322 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
324 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
325 represent a machine's physical PCI slots. The change in semantics
326 had userspace implications, as the hotplug core no longer allowed
327 drivers to create multiple sysfs files per physical slot (required
328 for multi-function devices, e.g.). fakephp was seen as a developer's
329 tool only, and its interface changed. Too late, we learned that
330 there were some users of the fakephp interface.
332 In 2.6.30, the original fakephp interface was restored. At the same
333 time, the PCI core gained the ability that fakephp provided, namely
334 function-level hot-remove and hot-add.
336 Since the PCI core now provides the same functionality, exposed in:
339 /sys/bus/pci/devices/.../remove
340 /sys/bus/pci/devices/.../rescan
342 there is no functional reason to maintain fakephp as well.
344 We will keep the existing module so that 'modprobe fakephp' will
345 present the old /sys/bus/pci/slots/... interface for compatibility,
346 but users are urged to migrate their applications to the API above.
348 After a reasonable transition period, we will remove the legacy
350 Who: Alex Chiang <achiang@hp.com>
352 ---------------------------
354 What: CONFIG_RFKILL_INPUT
356 Why: Should be implemented in userspace, policy daemon.
357 Who: Johannes Berg <johannes@sipsolutions.net>
359 ----------------------------
361 What: sound-slot/service-* module aliases and related clutters in
364 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
365 (14) and requests modules using custom sound-slot/service-*
366 module aliases. The only benefit of doing this is allowing
367 use of custom module aliases which might as well be considered
368 a bug at this point. This preemptive claiming prevents
369 alternative OSS implementations.
371 Till the feature is removed, the kernel will be requesting
372 both sound-slot/service-* and the standard char-major-* module
373 aliases and allow turning off the pre-claiming selectively via
374 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
377 After the transition phase is complete, both the custom module
378 aliases and switches to disable it will go away. This removal
379 will also allow making ALSA OSS emulation independent of
380 sound_core. The dependency will be broken then too.
381 Who: Tejun Heo <tj@kernel.org>
383 ----------------------------
385 What: Support for lcd_switch and display_get in asus-laptop driver
387 Why: These two features use non-standard interfaces. There are the
388 only features that really need multiple path to guess what's
389 the right method name on a specific laptop.
391 Removing them will allow to remove a lot of code an significantly
394 This will affect the backlight code which won't be able to know
395 if the backlight is on or off. The platform display file will also be
396 write only (like the one in eeepc-laptop).
398 This should'nt affect a lot of user because they usually know
399 when their display is on or off.
401 Who: Corentin Chary <corentin.chary@gmail.com>
403 ----------------------------
405 What: sysfs-class-rfkill state file
407 Files: net/rfkill/core.c
408 Why: Documented as obsolete since Feb 2010. This file is limited to 3
409 states while the rfkill drivers can have 4 states.
410 Who: anybody or Florian Mickler <florian@mickler.org>
412 ----------------------------
414 What: sysfs-class-rfkill claim file
416 Files: net/rfkill/core.c
417 Why: It is not possible to claim an rfkill driver since 2007. This is
418 Documented as obsolete since Feb 2010.
419 Who: anybody or Florian Mickler <florian@mickler.org>
421 ----------------------------
425 Files: drivers/isdn/capi/capifs.*
426 Why: udev fully replaces this special file system that only contains CAPI
427 NCCI TTY device nodes. User space (pppdcapiplugin) works without
428 noticing the difference.
429 Who: Jan Kiszka <jan.kiszka@web.de>
431 ----------------------------
433 What: KVM paravirt mmu host support
435 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
436 on newer and older hardware. It is already not exposed to the guest,
437 and kept only for live migration purposes.
438 Who: Avi Kivity <avi@redhat.com>
440 ----------------------------
442 What: iwlwifi 50XX module parameters
444 Why: The "..50" modules parameters were used to configure 5000 series and
445 up devices; different set of module parameters also available for 4965
446 with same functionalities. Consolidate both set into single place
447 in drivers/net/wireless/iwlwifi/iwl-agn.c
449 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
451 ----------------------------
453 What: iwl4965 alias support
455 Why: Internal alias support has been present in module-init-tools for some
456 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
459 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
461 ---------------------------
464 Files: net/netfilter/xt_NOTRACK.c
466 Why: Superseded by xt_CT
467 Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
469 ----------------------------
473 Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled
474 Who: Thomas Gleixner <tglx@linutronix.de>
476 ----------------------------
478 What: The acpi_sleep=s4_nonvs command line option
480 Files: arch/x86/kernel/acpi/sleep.c
481 Why: superseded by acpi_sleep=nonvs
482 Who: Rafael J. Wysocki <rjw@sisk.pl>
484 ----------------------------
486 What: PCI DMA unmap state API
488 Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
489 with DMA unmap state API (DMA unmap state API can be used for
491 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
493 ----------------------------
495 What: DMA_xxBIT_MASK macros
497 Why: DMA_xxBIT_MASK macros were replaced with DMA_BIT_MASK() macros.
498 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
500 ----------------------------
502 What: namespace cgroup (ns_cgroup)
504 Why: The ns_cgroup leads to some problems:
505 * cgroup creation is out-of-control
506 * cgroup name can conflict when pids are looping
507 * it is not possible to have a single process handling
508 a lot of namespaces without falling in a exponential creation time
509 * we may want to create a namespace without creating a cgroup
511 The ns_cgroup is replaced by a compatibility flag 'clone_children',
512 where a newly created cgroup will copy the parent cgroup values.
513 The userspace has to manually create a cgroup and add a task to
515 Who: Daniel Lezcano <daniel.lezcano@free.fr>
517 ----------------------------
519 What: iwlwifi disable_hw_scan module parameters
521 Why: Hareware scan is the prefer method for iwlwifi devices for
522 scanning operation. Remove software scan support for all the
525 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
527 ----------------------------
529 What: access to nfsd auth cache through sys_nfsservctl or '.' files
530 in the 'nfsd' filesystem.
532 Why: This is a legacy interface which have been replaced by a more
533 dynamic cache. Continuing to maintain this interface is an
535 Who: NeilBrown <neilb@suse.de>
537 ----------------------------
541 Why: This field is deprecated. I2C device drivers shouldn't change their
542 behavior based on the underlying I2C adapter. Instead, the I2C
543 adapter driver should instantiate the I2C devices and provide the
544 needed platform-specific information.
545 Who: Jean Delvare <khali@linux-fr.org>
547 ----------------------------