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: x86 floppy disable_hlt
11 Why: ancient workaround of dubious utility clutters the
12 code used by everybody else.
13 Who: Len Brown <len.brown@intel.com>
15 ---------------------------
17 What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
19 Why: This optional sub-feature of APM is of dubious reliability,
20 and ancient APM laptops are likely better served by calling HLT.
21 Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
22 the pm_idle function pointer to modules.
23 Who: Len Brown <len.brown@intel.com>
25 ----------------------------
27 What: x86_32 "no-hlt" cmdline param
29 Why: remove a branch from idle path, simplify code used by everybody.
30 This option disabled the use of HLT in idle and machine_halt()
31 for hardware that was flakey 15-years ago. Today we have
32 "idle=poll" that removed HLT from idle, and so if such a machine
33 is still running the upstream kernel, "idle=poll" is likely sufficient.
34 Who: Len Brown <len.brown@intel.com>
36 ----------------------------
38 What: x86 "idle=mwait" cmdline param
40 Why: simplify x86 idle code
41 Who: Len Brown <len.brown@intel.com>
43 ----------------------------
48 Why: prism54 FullMAC PCI / Cardbus devices used to be supported only by the
49 prism54 wireless driver. After Intersil stopped selling these
50 devices in preference for the newer more flexible SoftMAC devices
51 a SoftMAC device driver was required and prism54 did not support
52 them. The p54pci driver now exists and has been present in the kernel for
53 a while. This driver supports both SoftMAC devices and FullMAC devices.
54 The main difference between these devices was the amount of memory which
55 could be used for the firmware. The SoftMAC devices support a smaller
56 amount of memory. Because of this the SoftMAC firmware fits into FullMAC
57 devices's memory. p54pci supports not only PCI / Cardbus but also USB
58 and SPI. Since p54pci supports all devices prism54 supports
59 you will have a conflict. I'm not quite sure how distributions are
60 handling this conflict right now. prism54 was kept around due to
61 claims users may experience issues when using the SoftMAC driver.
62 Time has passed users have not reported issues. If you use prism54
63 and for whatever reason you cannot use p54pci please let us know!
64 E-mail us at: linux-wireless@vger.kernel.org
66 For more information see the p54 wiki page:
68 http://wireless.kernel.org/en/users/Drivers/p54
70 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
72 ---------------------------
74 What: IRQF_SAMPLE_RANDOM
75 Check: IRQF_SAMPLE_RANDOM
78 Why: Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy
79 sources in the kernel's current entropy model. To resolve this, every
80 input point to the kernel's entropy pool needs to better document the
81 type of entropy source it actually is. This will be replaced with
82 additional add_*_randomness functions in drivers/char/random.c
84 Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com>
86 ---------------------------
88 What: Deprecated snapshot ioctls
91 Why: The ioctls in kernel/power/user.c were marked as deprecated long time
92 ago. Now they notify users about that so that they need to replace
93 their userspace. After some more time, remove them completely.
95 Who: Jiri Slaby <jirislaby@gmail.com>
97 ---------------------------
99 What: The ieee80211_regdom module parameter
100 When: March 2010 / desktop catchup
102 Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
103 and currently serves as an option for users to define an
104 ISO / IEC 3166 alpha2 code for the country they are currently
105 present in. Although there are userspace API replacements for this
106 through nl80211 distributions haven't yet caught up with implementing
107 decent alternatives through standard GUIs. Although available as an
108 option through iw or wpa_supplicant its just a matter of time before
109 distributions pick up good GUI options for this. The ideal solution
110 would actually consist of intelligent designs which would do this for
111 the user automatically even when travelling through different countries.
112 Until then we leave this module parameter as a compromise.
114 When userspace improves with reasonable widely-available alternatives for
115 this we will no longer need this module parameter. This entry hopes that
116 by the super-futuristically looking date of "March 2010" we will have
117 such replacements widely available.
119 Who: Luis R. Rodriguez <lrodriguez@atheros.com>
121 ---------------------------
123 What: dev->power.power_state
125 Why: Broken design for runtime control over driver power states, confusing
126 driver-internal runtime power management with: mechanisms to support
127 system-wide sleep state transitions; event codes that distinguish
128 different phases of swsusp "sleep" transitions; and userspace policy
129 inputs. This framework was never widely used, and most attempts to
130 use it were broken. Drivers should instead be exposing domain-specific
131 interfaces either to kernel or to userspace.
132 Who: Pavel Machek <pavel@ucw.cz>
134 ---------------------------
136 What: /proc/<pid>/oom_adj
138 Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's
139 badness heuristic used to determine which task to kill when the kernel
142 The badness heuristic has since been rewritten since the introduction of
143 this tunable such that its meaning is deprecated. The value was
144 implemented as a bitshift on a score generated by the badness()
145 function that did not have any precise units of measure. With the
146 rewrite, the score is given as a proportion of available memory to the
147 task allocating pages, so using a bitshift which grows the score
148 exponentially is, thus, impossible to tune with fine granularity.
150 A much more powerful interface, /proc/<pid>/oom_score_adj, was
151 introduced with the oom killer rewrite that allows users to increase or
152 decrease the badness score linearly. This interface will replace
155 A warning will be emitted to the kernel log if an application uses this
156 deprecated interface. After it is printed once, future warnings will be
157 suppressed until the kernel is rebooted.
159 ---------------------------
161 What: remove EXPORT_SYMBOL(kernel_thread)
163 Files: arch/*/kernel/*_ksyms.c
165 Why: kernel_thread is a low-level implementation detail. Drivers should
166 use the <linux/kthread.h> API instead which shields them from
167 implementation details and provides a higherlevel interface that
168 prevents bugs and code duplication
169 Who: Christoph Hellwig <hch@lst.de>
171 ---------------------------
173 What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
174 (temporary transition config option provided until then)
175 The transition config option will also be removed at the same time.
177 Why: Unused symbols are both increasing the size of the kernel binary
178 and are often a sign of "wrong API"
179 Who: Arjan van de Ven <arjan@linux.intel.com>
181 ---------------------------
183 What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
185 Why: The stacking of class devices makes these values misleading and
187 Class devices should not carry any of these properties, and bus
188 devices have SUBSYTEM and DRIVER as a replacement.
189 Who: Kay Sievers <kay.sievers@suse.de>
191 ---------------------------
193 What: ACPI procfs interface
195 Why: ACPI sysfs conversion should be finished by January 2008.
196 ACPI procfs interface will be removed in July 2008 so that
197 there is enough time for the user space to catch up.
198 Who: Zhang Rui <rui.zhang@intel.com>
200 ---------------------------
202 What: CONFIG_ACPI_PROCFS_POWER
204 Why: sysfs I/F for ACPI power devices, including AC and Battery,
205 has been working in upstream kernel since 2.6.24, Sep 2007.
206 In 2.6.37, we make the sysfs I/F always built in and this option
208 Remove this option and the ACPI power procfs interface in 2.6.39.
209 Who: Zhang Rui <rui.zhang@intel.com>
211 ---------------------------
213 What: /proc/acpi/event
215 Why: /proc/acpi/event has been replaced by events via the input layer
216 and netlink since 2.6.23.
217 Who: Len Brown <len.brown@intel.com>
219 ---------------------------
221 What: i386/x86_64 bzImage symlinks
224 Why: The i386/x86_64 merge provides a symlink to the old bzImage
225 location so not yet updated user space tools, e.g. package
226 scripts, do not break.
227 Who: Thomas Gleixner <tglx@linutronix.de>
229 ---------------------------
231 What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib
233 Why: All callers should use explicit gpio_request()/gpio_free().
234 The autorequest mechanism in gpiolib was provided mostly as a
235 migration aid for legacy GPIO interfaces (for SOC based GPIOs).
236 Those users have now largely migrated. Platforms implementing
237 the GPIO interfaces without using gpiolib will see no changes.
238 Who: David Brownell <dbrownell@users.sourceforge.net>
239 ---------------------------
241 What: b43 support for firmware revision < 410
242 When: The schedule was July 2008, but it was decided that we are going to keep the
243 code as long as there are no major maintanance headaches.
244 So it _could_ be removed _any_ time now, if it conflicts with something new.
245 Why: The support code for the old firmware hurts code readability/maintainability
246 and slightly hurts runtime performance. Bugfixes for the old firmware
247 are not provided by Broadcom anymore.
248 Who: Michael Buesch <m@bues.ch>
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: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
265 (in net/core/net-sysfs.c)
267 Why: Over 1K .text/.data size reduction, data is available in other
269 Who: Johannes Berg <johannes@sipsolutions.net>
271 ---------------------------
273 What: sysfs ui for changing p4-clockmod parameters
275 Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
276 e088e4c9cdb618675874becb91b2fd581ee707e6.
277 Removal is subject to fixing any remaining bugs in ACPI which may
278 cause the thermal throttling not to happen at the right time.
279 Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
281 -----------------------------
283 What: fakephp and associated sysfs files in /sys/bus/pci/slots/
285 Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
286 represent a machine's physical PCI slots. The change in semantics
287 had userspace implications, as the hotplug core no longer allowed
288 drivers to create multiple sysfs files per physical slot (required
289 for multi-function devices, e.g.). fakephp was seen as a developer's
290 tool only, and its interface changed. Too late, we learned that
291 there were some users of the fakephp interface.
293 In 2.6.30, the original fakephp interface was restored. At the same
294 time, the PCI core gained the ability that fakephp provided, namely
295 function-level hot-remove and hot-add.
297 Since the PCI core now provides the same functionality, exposed in:
300 /sys/bus/pci/devices/.../remove
301 /sys/bus/pci/devices/.../rescan
303 there is no functional reason to maintain fakephp as well.
305 We will keep the existing module so that 'modprobe fakephp' will
306 present the old /sys/bus/pci/slots/... interface for compatibility,
307 but users are urged to migrate their applications to the API above.
309 After a reasonable transition period, we will remove the legacy
311 Who: Alex Chiang <achiang@hp.com>
313 ---------------------------
315 What: CONFIG_RFKILL_INPUT
317 Why: Should be implemented in userspace, policy daemon.
318 Who: Johannes Berg <johannes@sipsolutions.net>
320 ----------------------------
322 What: sound-slot/service-* module aliases and related clutters in
325 Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
326 (14) and requests modules using custom sound-slot/service-*
327 module aliases. The only benefit of doing this is allowing
328 use of custom module aliases which might as well be considered
329 a bug at this point. This preemptive claiming prevents
330 alternative OSS implementations.
332 Till the feature is removed, the kernel will be requesting
333 both sound-slot/service-* and the standard char-major-* module
334 aliases and allow turning off the pre-claiming selectively via
335 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
338 After the transition phase is complete, both the custom module
339 aliases and switches to disable it will go away. This removal
340 will also allow making ALSA OSS emulation independent of
341 sound_core. The dependency will be broken then too.
342 Who: Tejun Heo <tj@kernel.org>
344 ----------------------------
346 What: sysfs-class-rfkill state file
348 Files: net/rfkill/core.c
349 Why: Documented as obsolete since Feb 2010. This file is limited to 3
350 states while the rfkill drivers can have 4 states.
351 Who: anybody or Florian Mickler <florian@mickler.org>
353 ----------------------------
355 What: sysfs-class-rfkill claim file
357 Files: net/rfkill/core.c
358 Why: It is not possible to claim an rfkill driver since 2007. This is
359 Documented as obsolete since Feb 2010.
360 Who: anybody or Florian Mickler <florian@mickler.org>
362 ----------------------------
364 What: KVM paravirt mmu host support
366 Why: The paravirt mmu host support is slower than non-paravirt mmu, both
367 on newer and older hardware. It is already not exposed to the guest,
368 and kept only for live migration purposes.
369 Who: Avi Kivity <avi@redhat.com>
371 ----------------------------
373 What: iwlwifi 50XX module parameters
375 Why: The "..50" modules parameters were used to configure 5000 series and
376 up devices; different set of module parameters also available for 4965
377 with same functionalities. Consolidate both set into single place
378 in drivers/net/wireless/iwlwifi/iwl-agn.c
380 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
382 ----------------------------
384 What: iwl4965 alias support
386 Why: Internal alias support has been present in module-init-tools for some
387 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
390 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
392 ---------------------------
395 Files: net/netfilter/xt_NOTRACK.c
397 Why: Superseded by xt_CT
398 Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
400 ----------------------------
404 Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled
405 Who: Thomas Gleixner <tglx@linutronix.de>
407 ----------------------------
409 What: PCI DMA unmap state API
411 Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
412 with DMA unmap state API (DMA unmap state API can be used for
414 Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
416 ----------------------------
418 What: iwlwifi disable_hw_scan module parameters
420 Why: Hareware scan is the prefer method for iwlwifi devices for
421 scanning operation. Remove software scan support for all the
424 Who: Wey-Yi Guy <wey-yi.w.guy@intel.com>
426 ----------------------------
428 What: Legacy, non-standard chassis intrusion detection interface.
430 Why: The adm9240, w83792d and w83793 hardware monitoring drivers have
431 legacy interfaces for chassis intrusion detection. A standard
432 interface has been added to each driver, so the legacy interface
434 Who: Jean Delvare <khali@linux-fr.org>
436 ----------------------------
438 What: xt_connlimit rev 0
440 Who: Jan Engelhardt <jengelh@medozas.de>
441 Files: net/netfilter/xt_connlimit.c
443 ----------------------------
445 What: ipt_addrtype match include file
447 Why: superseded by xt_addrtype
448 Who: Florian Westphal <fw@strlen.de>
449 Files: include/linux/netfilter_ipv4/ipt_addrtype.h
451 ----------------------------
453 What: i2c_driver.attach_adapter
454 i2c_driver.detach_adapter
456 Why: These legacy callbacks should no longer be used as i2c-core offers
457 a variety of preferable alternative ways to instantiate I2C devices.
458 Who: Jean Delvare <khali@linux-fr.org>
460 ----------------------------
462 What: Support for driver specific ioctls in the pwc driver (everything
463 defined in media/pwc-ioctl.h)
465 Why: This stems from the v4l1 era, with v4l2 everything can be done with
466 standardized v4l2 API calls
467 Who: Hans de Goede <hdegoede@redhat.com>
469 ----------------------------
471 What: Driver specific sysfs API in the pwc driver
473 Why: Setting pan/tilt should be done with v4l2 controls, like with other
474 cams. The button is available as a standard input device
475 Who: Hans de Goede <hdegoede@redhat.com>
477 ----------------------------
479 What: Driver specific use of pixfmt.priv in the pwc driver
481 Why: The .priv field never was intended for this, setting a framerate is
482 support using the standardized S_PARM ioctl
483 Who: Hans de Goede <hdegoede@redhat.com>
485 ----------------------------
487 What: Software emulation of arbritary resolutions in the pwc driver
489 Why: The pwc driver claims to support any resolution between 160x120
490 and 640x480, but emulates this by simply drawing a black border
491 around the image. Userspace can draw its own black border if it
493 Who: Hans de Goede <hdegoede@redhat.com>
495 ----------------------------
497 What: For VIDIOC_S_FREQUENCY the type field must match the device node's type.
498 If not, return -EINVAL.
500 Why: It makes no sense to switch the tuner to radio mode by calling
501 VIDIOC_S_FREQUENCY on a video node, or to switch the tuner to tv mode by
502 calling VIDIOC_S_FREQUENCY on a radio node. This is the first step of a
503 move to more consistent handling of tv and radio tuners.
504 Who: Hans Verkuil <hans.verkuil@cisco.com>
506 ----------------------------
508 What: Opening a radio device node will no longer automatically switch the
509 tuner mode from tv to radio.
511 Why: Just opening a V4L device should not change the state of the hardware
512 like that. It's very unexpected and against the V4L spec. Instead, you
513 switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second
514 and last step of the move to consistent handling of tv and radio tuners.
515 Who: Hans Verkuil <hans.verkuil@cisco.com>
517 ----------------------------
519 What: g_file_storage driver
521 Why: This driver has been superseded by g_mass_storage.
522 Who: Alan Stern <stern@rowland.harvard.edu>
524 ----------------------------
526 What: threeg and interface sysfs files in /sys/devices/platform/acer-wmi
528 Why: In 3.0, we can now autodetect internal 3G device and already have
529 the threeg rfkill device. So, we plan to remove threeg sysfs support
530 for it's no longer necessary.
532 We also plan to remove interface sysfs file that exposed which ACPI-WMI
533 interface that was used by acer-wmi driver. It will replaced by
534 information log when acer-wmi initial.
535 Who: Lee, Chun-Yi <jlee@novell.com>
537 ----------------------------
539 What: The XFS nodelaylog mount option
541 Why: The delaylog mode that has been the default since 2.6.39 has proven
542 stable, and the old code is in the way of additional improvements in
544 Who: Christoph Hellwig <hch@lst.de>
546 ----------------------------
548 What: iwlagn alias support
550 Why: The iwlagn module has been renamed iwlwifi. The alias will be around
551 for backward compatibility for several cycles and then dropped.
552 Who: Don Fry <donald.h.fry@intel.com>