| blob | 05df0b7514b6b884d38c545f8bb838cdfeb1d162 |
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@suse.cz>
98 ---------------------------
100 What: Video4Linux API 1 ioctls and from Video devices.
101 When: July 2009
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
114 v4l1-compat module.
115 Who: Mauro Carvalho Chehab <mchehab@infradead.org>
117 ---------------------------
119 What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
120 When: 2.6.35/2.6.36
121 Files: drivers/pcmcia/: pcmcia_ioctl.c
122 Why: With the 16-bit PCMCIA subsystem now behaving (almost) like a
123 normal hotpluggable bus, and with it using the default kernel
124 infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
125 control ioctl needed by cardmgr and cardctl from pcmcia-cs is
126 unnecessary and potentially harmful (it does not provide for
127 proper locking), and makes further cleanups and integration of the
128 PCMCIA subsystem into the Linux kernel device driver model more
129 difficult. The features provided by cardmgr and cardctl are either
130 handled by the kernel itself now or are available in the new
131 pcmciautils package available at
132 http://kernel.org/pub/linux/utils/kernel/pcmcia/
134 For all architectures except ARM, the associated config symbol
135 has been removed from kernel 2.6.34; for ARM, it will be likely
136 be removed from kernel 2.6.35. The actual code will then likely
137 be removed from kernel 2.6.36.
138 Who: Dominik Brodowski <linux@dominikbrodowski.net>
140 ---------------------------
142 What: sys_sysctl
143 When: September 2010
144 Option: CONFIG_SYSCTL_SYSCALL
145 Why: The same information is available in a more convenient from
146 /proc/sys, and none of the sysctl variables appear to be
147 important performance wise.
149 Binary sysctls are a long standing source of subtle kernel
150 bugs and security issues.
152 When I looked several months ago all I could find after
153 searching several distributions were 5 user space programs and
154 glibc (which falls back to /proc/sys) using this syscall.
156 The man page for sysctl(2) documents it as unusable for user
157 space programs.
159 sysctl(2) is not generally ABI compatible to a 32bit user
160 space application on a 64bit and a 32bit kernel.
162 For the last several months the policy has been no new binary
163 sysctls and no one has put forward an argument to use them.
165 Binary sysctls issues seem to keep happening appearing so
166 properly deprecating them (with a warning to user space) and a
167 2 year grace warning period will mean eventually we can kill
168 them and end the pain.
170 In the mean time individual binary sysctls can be dealt with
171 in a piecewise fashion.
173 Who: Eric Biederman <ebiederm@xmission.com>
175 ---------------------------
177 What: remove EXPORT_SYMBOL(kernel_thread)
178 When: August 2006
179 Files: arch/*/kernel/*_ksyms.c
180 Check: kernel_thread
181 Why: kernel_thread is a low-level implementation detail. Drivers should
182 use the <linux/kthread.h> API instead which shields them from
183 implementation details and provides a higherlevel interface that
184 prevents bugs and code duplication
185 Who: Christoph Hellwig <hch@lst.de>
187 ---------------------------
189 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
190 (temporary transition config option provided until then)
191 The transition config option will also be removed at the same time.
192 When: before 2.6.19
193 Why: Unused symbols are both increasing the size of the kernel binary
194 and are often a sign of "wrong API"
195 Who: Arjan van de Ven <arjan@linux.intel.com>
197 ---------------------------
199 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
200 When: October 2008
201 Why: The stacking of class devices makes these values misleading and
202 inconsistent.
203 Class devices should not carry any of these properties, and bus
204 devices have SUBSYTEM and DRIVER as a replacement.
205 Who: Kay Sievers <kay.sievers@suse.de>
207 ---------------------------
209 What: ACPI procfs interface
210 When: July 2008
211 Why: ACPI sysfs conversion should be finished by January 2008.
212 ACPI procfs interface will be removed in July 2008 so that
213 there is enough time for the user space to catch up.
214 Who: Zhang Rui <rui.zhang@intel.com>
216 ---------------------------
218 What: /proc/acpi/button
219 When: August 2007
220 Why: /proc/acpi/button has been replaced by events to the input layer
221 since 2.6.20.
222 Who: Len Brown <len.brown@intel.com>
224 ---------------------------
226 What: /proc/acpi/event
227 When: February 2008
228 Why: /proc/acpi/event has been replaced by events via the input layer
229 and netlink since 2.6.23.
230 Who: Len Brown <len.brown@intel.com>
232 ---------------------------
234 What: i386/x86_64 bzImage symlinks
235 When: April 2010
237 Why: The i386/x86_64 merge provides a symlink to the old bzImage
238 location so not yet updated user space tools, e.g. package
239 scripts, do not break.
240 Who: Thomas Gleixner <tglx@linutronix.de>
242 ---------------------------
244 What (Why):
245 - xt_recent: the old ipt_recent proc dir
246 (superseded by /proc/net/xt_recent)
248 When: January 2009 or Linux 2.7.0, whichever comes first
249 Why: Superseded by newer revisions or modules
250 Who: Jan Engelhardt <jengelh@computergmbh.de>
252 ---------------------------
254 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
255 When: February 2010
256 Why: All callers should use explicit gpio_request()/gpio_free().
257 The autorequest mechanism in gpiolib was provided mostly as a
258 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
259 Those users have now largely migrated. Platforms implementing
260 the GPIO interfaces without using gpiolib will see no changes.
261 Who: David Brownell <dbrownell@users.sourceforge.net>
262 ---------------------------
264 What: b43 support for firmware revision < 410
265 When: The schedule was July 2008, but it was decided that we are going to keep the
266 code as long as there are no major maintanance headaches.
267 So it _could_ be removed _any_ time now, if it conflicts with something new.
268 Why: The support code for the old firmware hurts code readability/maintainability
269 and slightly hurts runtime performance. Bugfixes for the old firmware
270 are not provided by Broadcom anymore.
271 Who: Michael Buesch <mb@bu3sch.de>
273 ---------------------------
275 What: /sys/o2cb symlink
276 When: January 2010
277 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb
278 exists as a symlink for backwards compatibility for old versions of
279 ocfs2-tools. 2 years should be sufficient time to phase in new versions
280 which know to look in /sys/fs/o2cb.
281 Who: ocfs2-devel@oss.oracle.com
283 ---------------------------
285 What: Ability for non root users to shm_get hugetlb pages based on mlock
286 resource limits
287 When: 2.6.31
288 Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
289 have CAP_IPC_LOCK to be able to allocate shm segments backed by
290 huge pages. The mlock based rlimit check to allow shm hugetlb is
291 inconsistent with mmap based allocations. Hence it is being
292 deprecated.
293 Who: Ravikiran Thirumalai <kiran@scalex86.org>
295 ---------------------------
297 What: CONFIG_THERMAL_HWMON
298 When: January 2009
299 Why: This option was introduced just to allow older lm-sensors userspace
300 to keep working over the upgrade to 2.6.26. At the scheduled time of
301 removal fixed lm-sensors (2.x or 3.x) should be readily available.
302 Who: Rene Herman <rene.herman@gmail.com>
304 ---------------------------
306 What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
307 (in net/core/net-sysfs.c)
308 When: After the only user (hal) has seen a release with the patches
309 for enough time, probably some time in 2010.
310 Why: Over 1K .text/.data size reduction, data is available in other
311 ways (ioctls)
312 Who: Johannes Berg <johannes@sipsolutions.net>
314 ---------------------------
316 What: CONFIG_NF_CT_ACCT
317 When: 2.6.29
318 Why: Accounting can now be enabled/disabled without kernel recompilation.
319 Currently used only to set a default value for a feature that is also
320 controlled by a kernel/module/sysfs/sysctl parameter.
321 Who: Krzysztof Piotr Oledzki <ole@ans.pl>
323 ---------------------------
325 What: sysfs ui for changing p4-clockmod parameters
326 When: September 2009
327 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
328 e088e4c9cdb618675874becb91b2fd581ee707e6.
329 Removal is subject to fixing any remaining bugs in ACPI which may
330 cause the thermal throttling not to happen at the right time.
331 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
333 -----------------------------
335 What: __do_IRQ all in one fits nothing interrupt handler
336 When: 2.6.32
337 Why: __do_IRQ was kept for easy migration to the type flow handlers.
338 More than two years of migration time is enough.
339 Who: Thomas Gleixner <tglx@linutronix.de>
341 -----------------------------
343 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
344 When: 2011
345 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
346 represent a machine's physical PCI slots. The change in semantics
347 had userspace implications, as the hotplug core no longer allowed
348 drivers to create multiple sysfs files per physical slot (required
349 for multi-function devices, e.g.). fakephp was seen as a developer's
350 tool only, and its interface changed. Too late, we learned that
351 there were some users of the fakephp interface.
353 In 2.6.30, the original fakephp interface was restored. At the same
354 time, the PCI core gained the ability that fakephp provided, namely
355 function-level hot-remove and hot-add.
357 Since the PCI core now provides the same functionality, exposed in:
359 /sys/bus/pci/rescan
360 /sys/bus/pci/devices/.../remove
361 /sys/bus/pci/devices/.../rescan
363 there is no functional reason to maintain fakephp as well.
365 We will keep the existing module so that 'modprobe fakephp' will
366 present the old /sys/bus/pci/slots/... interface for compatibility,
367 but users are urged to migrate their applications to the API above.
369 After a reasonable transition period, we will remove the legacy
370 fakephp interface.
371 Who: Alex Chiang <achiang@hp.com>
373 ---------------------------
375 What: CONFIG_RFKILL_INPUT
376 When: 2.6.33
377 Why: Should be implemented in userspace, policy daemon.
378 Who: Johannes Berg <johannes@sipsolutions.net>
380 ---------------------------
382 What: CONFIG_INOTIFY
383 When: 2.6.33
384 Why: last user (audit) will be converted to the newer more generic
385 and more easily maintained fsnotify subsystem
386 Who: Eric Paris <eparis@redhat.com>
388 ----------------------------
390 What: lock_policy_rwsem_* and unlock_policy_rwsem_* will not be
391 exported interface anymore.
392 When: 2.6.33
393 Why: cpu_policy_rwsem has a new cleaner definition making it local to
394 cpufreq core and contained inside cpufreq.c. Other dependent
395 drivers should not use it in order to safely avoid lockdep issues.
396 Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
398 ----------------------------
400 What: sound-slot/service-* module aliases and related clutters in
401 sound/sound_core.c
402 When: August 2010
403 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
404 (14) and requests modules using custom sound-slot/service-*
405 module aliases. The only benefit of doing this is allowing
406 use of custom module aliases which might as well be considered
407 a bug at this point. This preemptive claiming prevents
408 alternative OSS implementations.
410 Till the feature is removed, the kernel will be requesting
411 both sound-slot/service-* and the standard char-major-* module
412 aliases and allow turning off the pre-claiming selectively via
413 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
414 kernel parameter.
416 After the transition phase is complete, both the custom module
417 aliases and switches to disable it will go away. This removal
418 will also allow making ALSA OSS emulation independent of
419 sound_core. The dependency will be broken then too.
420 Who: Tejun Heo <tj@kernel.org>
422 ----------------------------
424 What: Support for VMware's guest paravirtuliazation technique [VMI] will be
425 dropped.
426 When: 2.6.37 or earlier.
427 Why: With the recent innovations in CPU hardware acceleration technologies
428 from Intel and AMD, VMware ran a few experiments to compare these
429 techniques to guest paravirtualization technique on VMware's platform.
430 These hardware assisted virtualization techniques have outperformed the
431 performance benefits provided by VMI in most of the workloads. VMware
432 expects that these hardware features will be ubiquitous in a couple of
433 years, as a result, VMware has started a phased retirement of this
434 feature from the hypervisor. We will be removing this feature from the
435 Kernel too. Right now we are targeting 2.6.37 but can retire earlier if
436 technical reasons (read opportunity to remove major chunk of pvops)
437 arise.
439 Please note that VMI has always been an optimization and non-VMI kernels
440 still work fine on VMware's platform.
441 Latest versions of VMware's product which support VMI are,
442 Workstation 7.0 and VSphere 4.0 on ESX side, future maintainence
443 releases for these products will continue supporting VMI.
445 For more details about VMI retirement take a look at this,
446 http://blogs.vmware.com/guestosguide/2009/09/vmi-retirement.html
448 Who: Alok N Kataria <akataria@vmware.com>
450 ----------------------------
452 What: Support for lcd_switch and display_get in asus-laptop driver
453 When: March 2010
454 Why: These two features use non-standard interfaces. There are the
455 only features that really need multiple path to guess what's
456 the right method name on a specific laptop.
458 Removing them will allow to remove a lot of code an significantly
459 clean the drivers.
461 This will affect the backlight code which won't be able to know
462 if the backlight is on or off. The platform display file will also be
463 write only (like the one in eeepc-laptop).
465 This should'nt affect a lot of user because they usually know
466 when their display is on or off.
468 Who: Corentin Chary <corentin.chary@gmail.com>
470 ----------------------------
472 What: usbvideo quickcam_messenger driver
473 When: 2.6.35
474 Files: drivers/media/video/usbvideo/quickcam_messenger.[ch]
475 Why: obsolete v4l1 driver replaced by gspca_stv06xx
476 Who: Hans de Goede <hdegoede@redhat.com>
478 ----------------------------
480 What: ov511 v4l1 driver
481 When: 2.6.35
482 Files: drivers/media/video/ov511.[ch]
483 Why: obsolete v4l1 driver replaced by gspca_ov519
484 Who: Hans de Goede <hdegoede@redhat.com>
486 ----------------------------
488 What: w9968cf v4l1 driver
489 When: 2.6.35
490 Files: drivers/media/video/w9968cf*.[ch]
491 Why: obsolete v4l1 driver replaced by gspca_ov519
492 Who: Hans de Goede <hdegoede@redhat.com>
494 ----------------------------
496 What: ovcamchip sensor framework
497 When: 2.6.35
498 Files: drivers/media/video/ovcamchip/*
499 Why: Only used by obsoleted v4l1 drivers
500 Who: Hans de Goede <hdegoede@redhat.com>
502 ----------------------------
504 What: stv680 v4l1 driver
505 When: 2.6.35
506 Files: drivers/media/video/stv680.[ch]
507 Why: obsolete v4l1 driver replaced by gspca_stv0680
508 Who: Hans de Goede <hdegoede@redhat.com>
510 ----------------------------
512 What: zc0301 v4l driver
513 When: 2.6.35
514 Files: drivers/media/video/zc0301/*
515 Why: Duplicate functionality with the gspca_zc3xx driver, zc0301 only
516 supports 2 USB-ID's (because it only supports a limited set of
517 sensors) wich are also supported by the gspca_zc3xx driver
518 (which supports 53 USB-ID's in total)
519 Who: Hans de Goede <hdegoede@redhat.com>
521 ----------------------------
523 What: corgikbd, spitzkbd, tosakbd driver
524 When: 2.6.35
525 Files: drivers/input/keyboard/{corgi,spitz,tosa}kbd.c
526 Why: We now have a generic GPIO based matrix keyboard driver that
527 are fully capable of handling all the keys on these devices.
528 The original drivers manipulate the GPIO registers directly
529 and so are difficult to maintain.
530 Who: Eric Miao <eric.y.miao@gmail.com>
532 ----------------------------
534 What: corgi_ssp and corgi_ts driver
535 When: 2.6.35
536 Files: arch/arm/mach-pxa/corgi_ssp.c, drivers/input/touchscreen/corgi_ts.c
537 Why: The corgi touchscreen is now deprecated in favour of the generic
538 ads7846.c driver. The noise reduction technique used in corgi_ts.c,
539 that's to wait till vsync before ADC sampling, is also integrated into
540 ads7846 driver now. Provided that the original driver is not generic
541 and is difficult to maintain, it will be removed later.
542 Who: Eric Miao <eric.y.miao@gmail.com>
544 ----------------------------
546 What: capifs
547 When: February 2011
548 Files: drivers/isdn/capi/capifs.*
549 Why: udev fully replaces this special file system that only contains CAPI
550 NCCI TTY device nodes. User space (pppdcapiplugin) works without
551 noticing the difference.
552 Who: Jan Kiszka <jan.kiszka@web.de>
554 ----------------------------
556 What: KVM memory aliases support
557 When: July 2010
558 Why: Memory aliasing support is used for speeding up guest vga access
559 through the vga windows.
561 Modern userspace no longer uses this feature, so it's just bitrotted
562 code and can be removed with no impact.
563 Who: Avi Kivity <avi@redhat.com>
565 ----------------------------
567 What: KVM kernel-allocated memory slots
568 When: July 2010
569 Why: Since 2.6.25, kvm supports user-allocated memory slots, which are
570 much more flexible than kernel-allocated slots. All current userspace
571 supports the newer interface and this code can be removed with no
572 impact.
573 Who: Avi Kivity <avi@redhat.com>
575 ----------------------------
577 What: KVM paravirt mmu host support
578 When: January 2011
579 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
580 on newer and older hardware. It is already not exposed to the guest,
581 and kept only for live migration purposes.
582 Who: Avi Kivity <avi@redhat.com>
584 ----------------------------
586 What: "acpi=ht" boot option
587 When: 2.6.35
588 Why: Useful in 2003, implementation is a hack.
589 Generally invoked by accident today.
590 Seen as doing more harm than good.
591 Who: Len Brown <len.brown@intel.com>
593 ----------------------------
595 What: video4linux /dev/vtx teletext API support
596 When: 2.6.35
597 Files: drivers/media/video/saa5246a.c drivers/media/video/saa5249.c
598 include/linux/videotext.h
599 Why: The vtx device nodes have been superseded by vbi device nodes
600 for many years. No applications exist that use the vtx support.
601 Of the two i2c drivers that actually support this API the saa5249
602 has been impossible to use for a year now and no known hardware
603 that supports this device exists. The saa5246a is theoretically
604 supported by the old mxb boards, but it never actually worked.
606 In summary: there is no hardware that can use this API and there
607 are no applications actually implementing this API.
609 The vtx support still reserves minors 192-223 and we would really
610 like to reuse those for upcoming new functionality. In the unlikely
611 event that new hardware appears that wants to use the functionality
612 provided by the vtx API, then that functionality should be build
613 around the sliced VBI API instead.
614 Who: Hans Verkuil <hverkuil@xs4all.nl>