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 ---------------------------
41 Why: This driver is deprecated and the firmware is no longer
42 maintained. The replacement driver "carl9170" has been
43 around for a while, so the devices are still supported.
45 Who: Christian Lamparter <chunkeey@googlemail.com>
47 ---------------------------
49 What: IRQF_SAMPLE_RANDOM
50 Check: IRQF_SAMPLE_RANDOM
53 Why: Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy
54 sources in the kernel's current entropy model. To resolve this, every
55 input point to the kernel's entropy pool needs to better document the
56 type of entropy source it actually is. This will be replaced with
57 additional add_*_randomness functions in drivers/char/random.c
59 Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com>
61 ---------------------------
63 What: Deprecated snapshot ioctls
66 Why: The ioctls in kernel/power/user.c were marked as deprecated long time
67 ago. Now they notify users about that so that they need to replace
68 their userspace. After some more time, remove them completely.
70 Who: Jiri Slaby <jirislaby@gmail.com>
72 ---------------------------
74 What: The ieee80211_regdom module parameter
75 When: March 2010 / desktop catchup
77 Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
78 and currently serves as an option for users to define an
79 ISO / IEC 3166 alpha2 code for the country they are currently
80 present in. Although there are userspace API replacements for this
81 through nl80211 distributions haven't yet caught up with implementing
82 decent alternatives through standard GUIs. Although available as an
83 option through iw or wpa_supplicant its just a matter of time before
84 distributions pick up good GUI options for this. The ideal solution
85 would actually consist of intelligent designs which would do this for
86 the user automatically even when travelling through different countries.
87 Until then we leave this module parameter as a compromise.
89 When userspace improves with reasonable widely-available alternatives for
90 this we will no longer need this module parameter. This entry hopes that
91 by the super-futuristically looking date of "March 2010" we will have
92 such replacements widely available.
94 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
96 ---------------------------
98 What: dev->power.power_state
100 Why: Broken design for runtime control over driver power states, confusing
101 driver-internal runtime power management with: mechanisms to support
102 system-wide sleep state transitions; event codes that distinguish
103 different phases of swsusp "sleep" transitions; and userspace policy
104 inputs. This framework was never widely used, and most attempts to
105 use it were broken. Drivers should instead be exposing domain-specific
106 interfaces either to kernel or to userspace.
107 Who: Pavel Machek <pavel@ucw.cz>
109 ---------------------------
111 What: Video4Linux obsolete drivers using V4L1 API
113 Files: drivers/staging/se401/* drivers/staging/usbvideo/*
114 Check: drivers/staging/se401/se401.c drivers/staging/usbvideo/usbvideo.c
115 Why: There are some drivers still using V4L1 API, despite all efforts we've done
116 to migrate. Those drivers are for obsolete hardware that the old maintainer
117 didn't care (or not have the hardware anymore), and that no other developer
118 could find any hardware to buy. They probably have no practical usage today,
119 and people with such old hardware could probably keep using an older version
120 of the kernel. Those drivers will be moved to staging on 2.6.38 and, if nobody
121 cares enough to port and test them with V4L2 API, they'll be removed on 2.6.39.
122 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
124 ---------------------------
126 What: Video4Linux: Remove obsolete ioctl's
128 Files: include/media/videodev2.h
129 Why: Some ioctl's were defined wrong on 2.6.2 and 2.6.6, using the wrong
130 type of R/W arguments. They were fixed, but the old ioctl names are
131 still there, maintained to avoid breaking binary compatibility:
132 #define VIDIOC_OVERLAY_OLD _IOWR('V', 14, int)
133 #define VIDIOC_S_PARM_OLD _IOW('V', 22, struct v4l2_streamparm)
134 #define VIDIOC_S_CTRL_OLD _IOW('V', 28, struct v4l2_control)
135 #define VIDIOC_G_AUDIO_OLD _IOWR('V', 33, struct v4l2_audio)
136 #define VIDIOC_G_AUDOUT_OLD _IOWR('V', 49, struct v4l2_audioout)
137 #define VIDIOC_CROPCAP_OLD _IOR('V', 58, struct v4l2_cropcap)
138 There's no sense on preserving those forever, as it is very doubtful
139 that someone would try to use a such old binary with a modern kernel.
140 Removing them will allow us to remove some magic done at the V4L ioctl
143 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
145 ---------------------------
149 Option: CONFIG_SYSCTL_SYSCALL
150 Why: The same information is available in a more convenient from
151 /proc/sys, and none of the sysctl variables appear to be
152 important performance wise.
154 Binary sysctls are a long standing source of subtle kernel
155 bugs and security issues.
157 When I looked several months ago all I could find after
158 searching several distributions were 5 user space programs and
159 glibc (which falls back to /proc/sys) using this syscall.
161 The man page for sysctl(2) documents it as unusable for user
164 sysctl(2) is not generally ABI compatible to a 32bit user
165 space application on a 64bit and a 32bit kernel.
167 For the last several months the policy has been no new binary
168 sysctls and no one has put forward an argument to use them.
170 Binary sysctls issues seem to keep happening appearing so
171 properly deprecating them (with a warning to user space) and a
172 2 year grace warning period will mean eventually we can kill
173 them and end the pain.
175 In the mean time individual binary sysctls can be dealt with
176 in a piecewise fashion.
178 Who: Eric Biederman <ebiederm@xmission.com>
180 ---------------------------
182 What: /proc/<pid>/oom_adj
184 Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's
185 badness heuristic used to determine which task to kill when the kernel
188 The badness heuristic has since been rewritten since the introduction of
189 this tunable such that its meaning is deprecated. The value was
190 implemented as a bitshift on a score generated by the badness()
191 function that did not have any precise units of measure. With the
192 rewrite, the score is given as a proportion of available memory to the
193 task allocating pages, so using a bitshift which grows the score
194 exponentially is, thus, impossible to tune with fine granularity.
196 A much more powerful interface, /proc/<pid>/oom_score_adj, was
197 introduced with the oom killer rewrite that allows users to increase or
198 decrease the badness() score linearly. This interface will replace
201 A warning will be emitted to the kernel log if an application uses this
202 deprecated interface. After it is printed once, future warnings will be
203 suppressed until the kernel is rebooted.
205 ---------------------------
207 What: CS5535/CS5536 obsolete GPIO driver
209 Files: drivers/staging/cs5535_gpio/*
210 Check: drivers/staging/cs5535_gpio/cs5535_gpio.c
211 Why: A newer driver replaces this; it is drivers/gpio/cs5535-gpio.c, and
212 integrates with the Linux GPIO subsystem. The old driver has been
213 moved to staging, and will be removed altogether around 2.6.40.
214 Please test the new driver, and ensure that the functionality you
215 need and any bugfixes from the old driver are available in the new
217 Who: Andres Salomon <dilinger@queued.net>
219 --------------------------
221 What: remove EXPORT_SYMBOL(kernel_thread)
223 Files: arch/*/kernel/*_ksyms.c
225 Why: kernel_thread is a low-level implementation detail. Drivers should
226 use the <linux/kthread.h> API instead which shields them from
227 implementation details and provides a higherlevel interface that
228 prevents bugs and code duplication
229 Who: Christoph Hellwig <hch@lst.de>
231 ---------------------------
233 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
234 (temporary transition config option provided until then)
235 The transition config option will also be removed at the same time.
237 Why: Unused symbols are both increasing the size of the kernel binary
238 and are often a sign of "wrong API"
239 Who: Arjan van de Ven <arjan@linux.intel.com>
241 ---------------------------
243 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
245 Why: The stacking of class devices makes these values misleading and
247 Class devices should not carry any of these properties, and bus
248 devices have SUBSYTEM and DRIVER as a replacement.
249 Who: Kay Sievers <kay.sievers@suse.de>
251 ---------------------------
253 What: ACPI procfs interface
255 Why: ACPI sysfs conversion should be finished by January 2008.
256 ACPI procfs interface will be removed in July 2008 so that
257 there is enough time for the user space to catch up.
258 Who: Zhang Rui <rui.zhang@intel.com>
260 ---------------------------
262 What: CONFIG_ACPI_PROCFS_POWER
264 Why: sysfs I/F for ACPI power devices, including AC and Battery,
265 has been working in upstream kenrel since 2.6.24, Sep 2007.
266 In 2.6.37, we make the sysfs I/F always built in and this option
268 Remove this option and the ACPI power procfs interface in 2.6.39.
269 Who: Zhang Rui <rui.zhang@intel.com>
271 ---------------------------
273 What: /proc/acpi/button
275 Why: /proc/acpi/button has been replaced by events to the input layer
277 Who: Len Brown <len.brown@intel.com>
279 ---------------------------
281 What: /proc/acpi/event
283 Why: /proc/acpi/event has been replaced by events via the input layer
284 and netlink since 2.6.23.
285 Who: Len Brown <len.brown@intel.com>
287 ---------------------------
289 What: i386/x86_64 bzImage symlinks
292 Why: The i386/x86_64 merge provides a symlink to the old bzImage
293 location so not yet updated user space tools, e.g. package
294 scripts, do not break.
295 Who: Thomas Gleixner <tglx@linutronix.de>
297 ---------------------------
299 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
301 Why: All callers should use explicit gpio_request()/gpio_free().
302 The autorequest mechanism in gpiolib was provided mostly as a
303 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
304 Those users have now largely migrated. Platforms implementing
305 the GPIO interfaces without using gpiolib will see no changes.
306 Who: David Brownell <dbrownell@users.sourceforge.net>
307 ---------------------------
309 What: b43 support for firmware revision < 410
310 When: The schedule was July 2008, but it was decided that we are going to keep the
311 code as long as there are no major maintanance headaches.
312 So it _could_ be removed _any_ time now, if it conflicts with something new.
313 Why: The support code for the old firmware hurts code readability/maintainability
314 and slightly hurts runtime performance. Bugfixes for the old firmware
315 are not provided by Broadcom anymore.
316 Who: Michael Buesch <mb@bu3sch.de>
318 ---------------------------
320 What: /sys/o2cb symlink
322 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
323 exists as a symlink for backwards compatibility for old versions of
324 ocfs2-tools. 2 years should be sufficient time to phase in new versions
325 which know to look in /sys/fs/o2cb.
326 Who: ocfs2-devel@oss.oracle.com
328 ---------------------------
330 What: Ability for non root users to shm_get hugetlb pages based on mlock
333 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
334 have CAP_IPC_LOCK to be able to allocate shm segments backed by
335 huge pages. The mlock based rlimit check to allow shm hugetlb is
336 inconsistent with mmap based allocations. Hence it is being
338 Who: Ravikiran Thirumalai <kiran@scalex86.org>
340 ---------------------------
342 What: CONFIG_THERMAL_HWMON
344 Why: This option was introduced just to allow older lm-sensors userspace
345 to keep working over the upgrade to 2.6.26. At the scheduled time of
346 removal fixed lm-sensors (2.x or 3.x) should be readily available.
347 Who: Rene Herman <rene.herman@gmail.com>
349 ---------------------------
351 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
352 (in net/core/net-sysfs.c)
353 When: After the only user (hal) has seen a release with the patches
354 for enough time, probably some time in 2010.
355 Why: Over 1K .text/.data size reduction, data is available in other
357 Who: Johannes Berg <johannes@sipsolutions.net>
359 ---------------------------
361 What: sysfs ui for changing p4-clockmod parameters
363 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
364 e088e4c9cdb618675874becb91b2fd581ee707e6.
365 Removal is subject to fixing any remaining bugs in ACPI which may
366 cause the thermal throttling not to happen at the right time.
367 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
369 -----------------------------
371 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
373 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
374 represent a machine's physical PCI slots. The change in semantics
375 had userspace implications, as the hotplug core no longer allowed
376 drivers to create multiple sysfs files per physical slot (required
377 for multi-function devices, e.g.). fakephp was seen as a developer's
378 tool only, and its interface changed. Too late, we learned that
379 there were some users of the fakephp interface.
381 In 2.6.30, the original fakephp interface was restored. At the same
382 time, the PCI core gained the ability that fakephp provided, namely
383 function-level hot-remove and hot-add.
385 Since the PCI core now provides the same functionality, exposed in:
388 /sys/bus/pci/devices/.../remove
389 /sys/bus/pci/devices/.../rescan
391 there is no functional reason to maintain fakephp as well.
393 We will keep the existing module so that 'modprobe fakephp' will
394 present the old /sys/bus/pci/slots/... interface for compatibility,
395 but users are urged to migrate their applications to the API above.
397 After a reasonable transition period, we will remove the legacy
399 Who: Alex Chiang <achiang@hp.com>
401 ---------------------------
403 What: CONFIG_RFKILL_INPUT
405 Why: Should be implemented in userspace, policy daemon.
406 Who: Johannes Berg <johannes@sipsolutions.net>
408 ----------------------------
410 What: sound-slot/service-* module aliases and related clutters in
413 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
414 (14) and requests modules using custom sound-slot/service-*
415 module aliases. The only benefit of doing this is allowing
416 use of custom module aliases which might as well be considered
417 a bug at this point. This preemptive claiming prevents
418 alternative OSS implementations.
420 Till the feature is removed, the kernel will be requesting
421 both sound-slot/service-* and the standard char-major-* module
422 aliases and allow turning off the pre-claiming selectively via
423 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
426 After the transition phase is complete, both the custom module
427 aliases and switches to disable it will go away. This removal
428 will also allow making ALSA OSS emulation independent of
429 sound_core. The dependency will be broken then too.
430 Who: Tejun Heo <tj@kernel.org>
432 ----------------------------
434 What: Support for lcd_switch and display_get in asus-laptop driver
436 Why: These two features use non-standard interfaces. There are the
437 only features that really need multiple path to guess what's
438 the right method name on a specific laptop.
440 Removing them will allow to remove a lot of code an significantly
443 This will affect the backlight code which won't be able to know
444 if the backlight is on or off. The platform display file will also be
445 write only (like the one in eeepc-laptop).
447 This should'nt affect a lot of user because they usually know
448 when their display is on or off.
450 Who: Corentin Chary <corentin.chary@gmail.com>
452 ----------------------------
454 What: sysfs-class-rfkill state file
456 Files: net/rfkill/core.c
457 Why: Documented as obsolete since Feb 2010. This file is limited to 3
458 states while the rfkill drivers can have 4 states.
459 Who: anybody or Florian Mickler <florian@mickler.org>
461 ----------------------------
463 What: sysfs-class-rfkill claim file
465 Files: net/rfkill/core.c
466 Why: It is not possible to claim an rfkill driver since 2007. This is
467 Documented as obsolete since Feb 2010.
468 Who: anybody or Florian Mickler <florian@mickler.org>
470 ----------------------------
474 Files: drivers/isdn/capi/capifs.*
475 Why: udev fully replaces this special file system that only contains CAPI
476 NCCI TTY device nodes. User space (pppdcapiplugin) works without
477 noticing the difference.
478 Who: Jan Kiszka <jan.kiszka@web.de>
480 ----------------------------
482 What: KVM paravirt mmu host support
484 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
485 on newer and older hardware. It is already not exposed to the guest,
486 and kept only for live migration purposes.
487 Who: Avi Kivity <avi@redhat.com>
489 ----------------------------
491 What: iwlwifi 50XX module parameters
493 Why: The "..50" modules parameters were used to configure 5000 series and
494 up devices; different set of module parameters also available for 4965
495 with same functionalities. Consolidate both set into single place
496 in drivers/net/wireless/iwlwifi/iwl-agn.c
498 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
500 ----------------------------
502 What: iwl4965 alias support
504 Why: Internal alias support has been present in module-init-tools for some
505 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
508 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
510 ---------------------------
513 Files: net/netfilter/xt_NOTRACK.c
515 Why: Superseded by xt_CT
516 Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
518 ----------------------------
522 Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled
523 Who: Thomas Gleixner <tglx@linutronix.de>
525 ----------------------------
527 What: The acpi_sleep=s4_nonvs command line option
529 Files: arch/x86/kernel/acpi/sleep.c
530 Why: superseded by acpi_sleep=nonvs
531 Who: Rafael J. Wysocki <rjw@sisk.pl>
533 ----------------------------
535 What: PCI DMA unmap state API
537 Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
538 with DMA unmap state API (DMA unmap state API can be used for
540 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
542 ----------------------------
544 What: DMA_xxBIT_MASK macros
546 Why: DMA_xxBIT_MASK macros were replaced with DMA_BIT_MASK() macros.
547 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
549 ----------------------------
551 What: namespace cgroup (ns_cgroup)
553 Why: The ns_cgroup leads to some problems:
554 * cgroup creation is out-of-control
555 * cgroup name can conflict when pids are looping
556 * it is not possible to have a single process handling
557 a lot of namespaces without falling in a exponential creation time
558 * we may want to create a namespace without creating a cgroup
560 The ns_cgroup is replaced by a compatibility flag 'clone_children',
561 where a newly created cgroup will copy the parent cgroup values.
562 The userspace has to manually create a cgroup and add a task to
564 Who: Daniel Lezcano <daniel.lezcano@free.fr>
566 ----------------------------
568 What: iwlwifi disable_hw_scan module parameters
570 Why: Hareware scan is the prefer method for iwlwifi devices for
571 scanning operation. Remove software scan support for all the
574 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
576 ----------------------------
578 What: access to nfsd auth cache through sys_nfsservctl or '.' files
579 in the 'nfsd' filesystem.
581 Why: This is a legacy interface which have been replaced by a more
582 dynamic cache. Continuing to maintain this interface is an
584 Who: NeilBrown <neilb@suse.de>
586 ----------------------------
588 What: cancel_rearming_delayed_work[queue]()
591 Why: The functions have been superceded by cancel_delayed_work_sync()
592 quite some time ago. The conversion is trivial and there is no
594 Who: Tejun Heo <tj@kernel.org>
596 ----------------------------
598 What: Legacy, non-standard chassis intrusion detection interface.
600 Why: The adm9240, w83792d and w83793 hardware monitoring drivers have
601 legacy interfaces for chassis intrusion detection. A standard
602 interface has been added to each driver, so the legacy interface
604 Who: Jean Delvare <khali@linux-fr.org>
606 ----------------------------
608 What: xt_connlimit rev 0
610 Who: Jan Engelhardt <jengelh@medozas.de>
611 Files: net/netfilter/xt_connlimit.c
613 ----------------------------
615 What: noswapaccount kernel command line parameter
617 Why: The original implementation of memsw feature enabled by
618 CONFIG_CGROUP_MEM_RES_CTLR_SWAP could be disabled by the noswapaccount
619 kernel parameter (introduced in 2.6.29-rc1). Later on, this decision
620 turned out to be not ideal because we cannot have the feature compiled
621 in and disabled by default and let only interested to enable it
622 (e.g. general distribution kernels might need it). Therefore we have
623 added swapaccount[=0|1] parameter (introduced in 2.6.37) which provides
624 the both possibilities. If we remove noswapaccount we will have
625 less command line parameters with the same functionality and we
626 can also cleanup the parameter handling a bit ().
627 Who: Michal Hocko <mhocko@suse.cz>
629 ----------------------------
631 What: ipt_addrtype match include file
633 Why: superseded by xt_addrtype
634 Who: Florian Westphal <fw@strlen.de>
635 Files: include/linux/netfilter_ipv4/ipt_addrtype.h
637 ----------------------------
639 What: i2c_driver.attach_adapter
640 i2c_driver.detach_adapter
642 Why: These legacy callbacks should no longer be used as i2c-core offers
643 a variety of preferable alternative ways to instantiate I2C devices.
644 Who: Jean Delvare <khali@linux-fr.org>
646 ----------------------------