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@suse.cz>
98 ---------------------------
100 What: Video4Linux API 1 ioctls and from Video devices.
102 Files: include/linux/videodev.h
103 Check: include/linux/videodev.h
104 Why: V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
105 series. The old API have lots of drawbacks and don't provide enough
106 means to work with all video and audio standards. The newer API is
107 already available on the main drivers and should be used instead.
108 Newer drivers should use v4l_compat_translate_ioctl function to handle
109 old calls, replacing to newer ones.
110 Decoder iocts are using internally to allow video drivers to
111 communicate with video decoders. This should also be improved to allow
112 V4L2 calls being translated into compatible internal ioctls.
113 Compatibility ioctls will be provided, for a while, via
115 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
117 ---------------------------
121 Option: CONFIG_SYSCTL_SYSCALL
122 Why: The same information is available in a more convenient from
123 /proc/sys, and none of the sysctl variables appear to be
124 important performance wise.
126 Binary sysctls are a long standing source of subtle kernel
127 bugs and security issues.
129 When I looked several months ago all I could find after
130 searching several distributions were 5 user space programs and
131 glibc (which falls back to /proc/sys) using this syscall.
133 The man page for sysctl(2) documents it as unusable for user
136 sysctl(2) is not generally ABI compatible to a 32bit user
137 space application on a 64bit and a 32bit kernel.
139 For the last several months the policy has been no new binary
140 sysctls and no one has put forward an argument to use them.
142 Binary sysctls issues seem to keep happening appearing so
143 properly deprecating them (with a warning to user space) and a
144 2 year grace warning period will mean eventually we can kill
145 them and end the pain.
147 In the mean time individual binary sysctls can be dealt with
148 in a piecewise fashion.
150 Who: Eric Biederman <ebiederm@xmission.com>
152 ---------------------------
154 What: remove EXPORT_SYMBOL(kernel_thread)
156 Files: arch/*/kernel/*_ksyms.c
158 Why: kernel_thread is a low-level implementation detail. Drivers should
159 use the <linux/kthread.h> API instead which shields them from
160 implementation details and provides a higherlevel interface that
161 prevents bugs and code duplication
162 Who: Christoph Hellwig <hch@lst.de>
164 ---------------------------
166 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
167 (temporary transition config option provided until then)
168 The transition config option will also be removed at the same time.
170 Why: Unused symbols are both increasing the size of the kernel binary
171 and are often a sign of "wrong API"
172 Who: Arjan van de Ven <arjan@linux.intel.com>
174 ---------------------------
176 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
178 Why: The stacking of class devices makes these values misleading and
180 Class devices should not carry any of these properties, and bus
181 devices have SUBSYTEM and DRIVER as a replacement.
182 Who: Kay Sievers <kay.sievers@suse.de>
184 ---------------------------
186 What: ACPI procfs interface
188 Why: ACPI sysfs conversion should be finished by January 2008.
189 ACPI procfs interface will be removed in July 2008 so that
190 there is enough time for the user space to catch up.
191 Who: Zhang Rui <rui.zhang@intel.com>
193 ---------------------------
195 What: /proc/acpi/button
197 Why: /proc/acpi/button has been replaced by events to the input layer
199 Who: Len Brown <len.brown@intel.com>
201 ---------------------------
203 What: /proc/acpi/event
205 Why: /proc/acpi/event has been replaced by events via the input layer
206 and netlink since 2.6.23.
207 Who: Len Brown <len.brown@intel.com>
209 ---------------------------
211 What: i386/x86_64 bzImage symlinks
214 Why: The i386/x86_64 merge provides a symlink to the old bzImage
215 location so not yet updated user space tools, e.g. package
216 scripts, do not break.
217 Who: Thomas Gleixner <tglx@linutronix.de>
219 ---------------------------
221 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
223 Why: All callers should use explicit gpio_request()/gpio_free().
224 The autorequest mechanism in gpiolib was provided mostly as a
225 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
226 Those users have now largely migrated. Platforms implementing
227 the GPIO interfaces without using gpiolib will see no changes.
228 Who: David Brownell <dbrownell@users.sourceforge.net>
229 ---------------------------
231 What: b43 support for firmware revision < 410
232 When: The schedule was July 2008, but it was decided that we are going to keep the
233 code as long as there are no major maintanance headaches.
234 So it _could_ be removed _any_ time now, if it conflicts with something new.
235 Why: The support code for the old firmware hurts code readability/maintainability
236 and slightly hurts runtime performance. Bugfixes for the old firmware
237 are not provided by Broadcom anymore.
238 Who: Michael Buesch <mb@bu3sch.de>
240 ---------------------------
242 What: /sys/o2cb symlink
244 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
245 exists as a symlink for backwards compatibility for old versions of
246 ocfs2-tools. 2 years should be sufficient time to phase in new versions
247 which know to look in /sys/fs/o2cb.
248 Who: ocfs2-devel@oss.oracle.com
250 ---------------------------
252 What: Ability for non root users to shm_get hugetlb pages based on mlock
255 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
256 have CAP_IPC_LOCK to be able to allocate shm segments backed by
257 huge pages. The mlock based rlimit check to allow shm hugetlb is
258 inconsistent with mmap based allocations. Hence it is being
260 Who: Ravikiran Thirumalai <kiran@scalex86.org>
262 ---------------------------
264 What: CONFIG_THERMAL_HWMON
266 Why: This option was introduced just to allow older lm-sensors userspace
267 to keep working over the upgrade to 2.6.26. At the scheduled time of
268 removal fixed lm-sensors (2.x or 3.x) should be readily available.
269 Who: Rene Herman <rene.herman@gmail.com>
271 ---------------------------
273 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
274 (in net/core/net-sysfs.c)
275 When: After the only user (hal) has seen a release with the patches
276 for enough time, probably some time in 2010.
277 Why: Over 1K .text/.data size reduction, data is available in other
279 Who: Johannes Berg <johannes@sipsolutions.net>
281 ---------------------------
283 What: CONFIG_NF_CT_ACCT
285 Why: Accounting can now be enabled/disabled without kernel recompilation.
286 Currently used only to set a default value for a feature that is also
287 controlled by a kernel/module/sysfs/sysctl parameter.
288 Who: Krzysztof Piotr Oledzki <ole@ans.pl>
290 ---------------------------
292 What: sysfs ui for changing p4-clockmod parameters
294 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
295 e088e4c9cdb618675874becb91b2fd581ee707e6.
296 Removal is subject to fixing any remaining bugs in ACPI which may
297 cause the thermal throttling not to happen at the right time.
298 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
300 -----------------------------
302 What: __do_IRQ all in one fits nothing interrupt handler
304 Why: __do_IRQ was kept for easy migration to the type flow handlers.
305 More than two years of migration time is enough.
306 Who: Thomas Gleixner <tglx@linutronix.de>
308 -----------------------------
310 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
312 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
313 represent a machine's physical PCI slots. The change in semantics
314 had userspace implications, as the hotplug core no longer allowed
315 drivers to create multiple sysfs files per physical slot (required
316 for multi-function devices, e.g.). fakephp was seen as a developer's
317 tool only, and its interface changed. Too late, we learned that
318 there were some users of the fakephp interface.
320 In 2.6.30, the original fakephp interface was restored. At the same
321 time, the PCI core gained the ability that fakephp provided, namely
322 function-level hot-remove and hot-add.
324 Since the PCI core now provides the same functionality, exposed in:
327 /sys/bus/pci/devices/.../remove
328 /sys/bus/pci/devices/.../rescan
330 there is no functional reason to maintain fakephp as well.
332 We will keep the existing module so that 'modprobe fakephp' will
333 present the old /sys/bus/pci/slots/... interface for compatibility,
334 but users are urged to migrate their applications to the API above.
336 After a reasonable transition period, we will remove the legacy
338 Who: Alex Chiang <achiang@hp.com>
340 ---------------------------
342 What: CONFIG_RFKILL_INPUT
344 Why: Should be implemented in userspace, policy daemon.
345 Who: Johannes Berg <johannes@sipsolutions.net>
347 ---------------------------
351 Why: last user (audit) will be converted to the newer more generic
352 and more easily maintained fsnotify subsystem
353 Who: Eric Paris <eparis@redhat.com>
355 ----------------------------
357 What: lock_policy_rwsem_* and unlock_policy_rwsem_* will not be
358 exported interface anymore.
360 Why: cpu_policy_rwsem has a new cleaner definition making it local to
361 cpufreq core and contained inside cpufreq.c. Other dependent
362 drivers should not use it in order to safely avoid lockdep issues.
363 Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
365 ----------------------------
367 What: sound-slot/service-* module aliases and related clutters in
370 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
371 (14) and requests modules using custom sound-slot/service-*
372 module aliases. The only benefit of doing this is allowing
373 use of custom module aliases which might as well be considered
374 a bug at this point. This preemptive claiming prevents
375 alternative OSS implementations.
377 Till the feature is removed, the kernel will be requesting
378 both sound-slot/service-* and the standard char-major-* module
379 aliases and allow turning off the pre-claiming selectively via
380 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
383 After the transition phase is complete, both the custom module
384 aliases and switches to disable it will go away. This removal
385 will also allow making ALSA OSS emulation independent of
386 sound_core. The dependency will be broken then too.
387 Who: Tejun Heo <tj@kernel.org>
389 ----------------------------
391 What: Support for VMware's guest paravirtuliazation technique [VMI] will be
393 When: 2.6.37 or earlier.
394 Why: With the recent innovations in CPU hardware acceleration technologies
395 from Intel and AMD, VMware ran a few experiments to compare these
396 techniques to guest paravirtualization technique on VMware's platform.
397 These hardware assisted virtualization techniques have outperformed the
398 performance benefits provided by VMI in most of the workloads. VMware
399 expects that these hardware features will be ubiquitous in a couple of
400 years, as a result, VMware has started a phased retirement of this
401 feature from the hypervisor. We will be removing this feature from the
402 Kernel too. Right now we are targeting 2.6.37 but can retire earlier if
403 technical reasons (read opportunity to remove major chunk of pvops)
406 Please note that VMI has always been an optimization and non-VMI kernels
407 still work fine on VMware's platform.
408 Latest versions of VMware's product which support VMI are,
409 Workstation 7.0 and VSphere 4.0 on ESX side, future maintainence
410 releases for these products will continue supporting VMI.
412 For more details about VMI retirement take a look at this,
413 http://blogs.vmware.com/guestosguide/2009/09/vmi-retirement.html
415 Who: Alok N Kataria <akataria@vmware.com>
417 ----------------------------
419 What: Support for lcd_switch and display_get in asus-laptop driver
421 Why: These two features use non-standard interfaces. There are the
422 only features that really need multiple path to guess what's
423 the right method name on a specific laptop.
425 Removing them will allow to remove a lot of code an significantly
428 This will affect the backlight code which won't be able to know
429 if the backlight is on or off. The platform display file will also be
430 write only (like the one in eeepc-laptop).
432 This should'nt affect a lot of user because they usually know
433 when their display is on or off.
435 Who: Corentin Chary <corentin.chary@gmail.com>
437 ----------------------------
439 What: usbvideo quickcam_messenger driver
441 Files: drivers/media/video/usbvideo/quickcam_messenger.[ch]
442 Why: obsolete v4l1 driver replaced by gspca_stv06xx
443 Who: Hans de Goede <hdegoede@redhat.com>
445 ----------------------------
447 What: ov511 v4l1 driver
449 Files: drivers/media/video/ov511.[ch]
450 Why: obsolete v4l1 driver replaced by gspca_ov519
451 Who: Hans de Goede <hdegoede@redhat.com>
453 ----------------------------
455 What: w9968cf v4l1 driver
457 Files: drivers/media/video/w9968cf*.[ch]
458 Why: obsolete v4l1 driver replaced by gspca_ov519
459 Who: Hans de Goede <hdegoede@redhat.com>
461 ----------------------------
463 What: ovcamchip sensor framework
465 Files: drivers/media/video/ovcamchip/*
466 Why: Only used by obsoleted v4l1 drivers
467 Who: Hans de Goede <hdegoede@redhat.com>
469 ----------------------------
471 What: stv680 v4l1 driver
473 Files: drivers/media/video/stv680.[ch]
474 Why: obsolete v4l1 driver replaced by gspca_stv0680
475 Who: Hans de Goede <hdegoede@redhat.com>
477 ----------------------------
479 What: zc0301 v4l driver
481 Files: drivers/media/video/zc0301/*
482 Why: Duplicate functionality with the gspca_zc3xx driver, zc0301 only
483 supports 2 USB-ID's (because it only supports a limited set of
484 sensors) wich are also supported by the gspca_zc3xx driver
485 (which supports 53 USB-ID's in total)
486 Who: Hans de Goede <hdegoede@redhat.com>
488 ----------------------------
490 What: sysfs-class-rfkill state file
492 Files: net/rfkill/core.c
493 Why: Documented as obsolete since Feb 2010. This file is limited to 3
494 states while the rfkill drivers can have 4 states.
495 Who: anybody or Florian Mickler <florian@mickler.org>
497 ----------------------------
499 What: sysfs-class-rfkill claim file
501 Files: net/rfkill/core.c
502 Why: It is not possible to claim an rfkill driver since 2007. This is
503 Documented as obsolete since Feb 2010.
504 Who: anybody or Florian Mickler <florian@mickler.org>
506 ----------------------------
510 Files: drivers/isdn/capi/capifs.*
511 Why: udev fully replaces this special file system that only contains CAPI
512 NCCI TTY device nodes. User space (pppdcapiplugin) works without
513 noticing the difference.
514 Who: Jan Kiszka <jan.kiszka@web.de>
516 ----------------------------
518 What: KVM memory aliases support
520 Why: Memory aliasing support is used for speeding up guest vga access
521 through the vga windows.
523 Modern userspace no longer uses this feature, so it's just bitrotted
524 code and can be removed with no impact.
525 Who: Avi Kivity <avi@redhat.com>
527 ----------------------------
529 What: xtime, wall_to_monotonic
531 Files: kernel/time/timekeeping.c include/linux/time.h
532 Why: Cleaning up timekeeping internal values. Please use
533 existing timekeeping accessor functions to access
534 the equivalent functionality.
535 Who: John Stultz <johnstul@us.ibm.com>
537 ----------------------------
539 What: KVM kernel-allocated memory slots
541 Why: Since 2.6.25, kvm supports user-allocated memory slots, which are
542 much more flexible than kernel-allocated slots. All current userspace
543 supports the newer interface and this code can be removed with no
545 Who: Avi Kivity <avi@redhat.com>
547 ----------------------------
549 What: KVM paravirt mmu host support
551 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
552 on newer and older hardware. It is already not exposed to the guest,
553 and kept only for live migration purposes.
554 Who: Avi Kivity <avi@redhat.com>
556 ----------------------------
558 What: iwlwifi 50XX module parameters
560 Why: The "..50" modules parameters were used to configure 5000 series and
561 up devices; different set of module parameters also available for 4965
562 with same functionalities. Consolidate both set into single place
563 in drivers/net/wireless/iwlwifi/iwl-agn.c
565 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
567 ----------------------------
569 What: iwl4965 alias support
571 Why: Internal alias support has been present in module-init-tools for some
572 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
575 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
577 ---------------------------
580 Files: net/netfilter/xt_NOTRACK.c
582 Why: Superseded by xt_CT
583 Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
585 ---------------------------
587 What: video4linux /dev/vtx teletext API support
589 Files: drivers/media/video/saa5246a.c drivers/media/video/saa5249.c
590 include/linux/videotext.h
591 Why: The vtx device nodes have been superseded by vbi device nodes
592 for many years. No applications exist that use the vtx support.
593 Of the two i2c drivers that actually support this API the saa5249
594 has been impossible to use for a year now and no known hardware
595 that supports this device exists. The saa5246a is theoretically
596 supported by the old mxb boards, but it never actually worked.
598 In summary: there is no hardware that can use this API and there
599 are no applications actually implementing this API.
601 The vtx support still reserves minors 192-223 and we would really
602 like to reuse those for upcoming new functionality. In the unlikely
603 event that new hardware appears that wants to use the functionality
604 provided by the vtx API, then that functionality should be build
605 around the sliced VBI API instead.
606 Who: Hans Verkuil <hverkuil@xs4all.nl>
608 ----------------------------
612 Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled
613 Who: Thomas Gleixner <tglx@linutronix.de>
615 ----------------------------
617 What: old ieee1394 subsystem (CONFIG_IEEE1394)
619 Files: drivers/ieee1394/ except init_ohci1394_dma.c
620 Why: superseded by drivers/firewire/ (CONFIG_FIREWIRE) which offers more
621 features, better performance, and better security, all with smaller
622 and more modern code base
623 Who: Stefan Richter <stefanr@s5r6.in-berlin.de>
625 ----------------------------