| The following is a list of files and features that are going to be |
| removed in the kernel source tree. Every entry should contain what |
| exactly is going away, why it is happening, and who is going to be doing |
| the work. When the feature is removed from the kernel, it should also |
| be removed from this file. |
| |
| --------------------------- |
| |
| What: x86 floppy disable_hlt |
| When: 2012 |
| Why: ancient workaround of dubious utility clutters the |
| code used by everybody else. |
| Who: Len Brown <len.brown@intel.com> |
| |
| --------------------------- |
| |
| What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle |
| When: 2012 |
| Why: This optional sub-feature of APM is of dubious reliability, |
| and ancient APM laptops are likely better served by calling HLT. |
| Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting |
| the pm_idle function pointer to modules. |
| Who: Len Brown <len.brown@intel.com> |
| |
| ---------------------------- |
| |
| What: x86_32 "no-hlt" cmdline param |
| When: 2012 |
| Why: remove a branch from idle path, simplify code used by everybody. |
| This option disabled the use of HLT in idle and machine_halt() |
| for hardware that was flakey 15-years ago. Today we have |
| "idle=poll" that removed HLT from idle, and so if such a machine |
| is still running the upstream kernel, "idle=poll" is likely sufficient. |
| Who: Len Brown <len.brown@intel.com> |
| |
| ---------------------------- |
| |
| What: x86 "idle=mwait" cmdline param |
| When: 2012 |
| Why: simplify x86 idle code |
| Who: Len Brown <len.brown@intel.com> |
| |
| ---------------------------- |
| |
| What: PRISM54 |
| When: 2.6.34 |
| |
| Why: prism54 FullMAC PCI / Cardbus devices used to be supported only by the |
| prism54 wireless driver. After Intersil stopped selling these |
| devices in preference for the newer more flexible SoftMAC devices |
| a SoftMAC device driver was required and prism54 did not support |
| them. The p54pci driver now exists and has been present in the kernel for |
| a while. This driver supports both SoftMAC devices and FullMAC devices. |
| The main difference between these devices was the amount of memory which |
| could be used for the firmware. The SoftMAC devices support a smaller |
| amount of memory. Because of this the SoftMAC firmware fits into FullMAC |
| devices's memory. p54pci supports not only PCI / Cardbus but also USB |
| and SPI. Since p54pci supports all devices prism54 supports |
| you will have a conflict. I'm not quite sure how distributions are |
| handling this conflict right now. prism54 was kept around due to |
| claims users may experience issues when using the SoftMAC driver. |
| Time has passed users have not reported issues. If you use prism54 |
| and for whatever reason you cannot use p54pci please let us know! |
| E-mail us at: linux-wireless@vger.kernel.org |
| |
| For more information see the p54 wiki page: |
| |
| http://wireless.kernel.org/en/users/Drivers/p54 |
| |
| Who: Luis R. Rodriguez <lrodriguez@atheros.com> |
| |
| --------------------------- |
| |
| What: IRQF_SAMPLE_RANDOM |
| Check: IRQF_SAMPLE_RANDOM |
| When: July 2009 |
| |
| Why: Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy |
| sources in the kernel's current entropy model. To resolve this, every |
| input point to the kernel's entropy pool needs to better document the |
| type of entropy source it actually is. This will be replaced with |
| additional add_*_randomness functions in drivers/char/random.c |
| |
| Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com> |
| |
| --------------------------- |
| |
| What: Deprecated snapshot ioctls |
| When: 2.6.36 |
| |
| Why: The ioctls in kernel/power/user.c were marked as deprecated long time |
| ago. Now they notify users about that so that they need to replace |
| their userspace. After some more time, remove them completely. |
| |
| Who: Jiri Slaby <jirislaby@gmail.com> |
| |
| --------------------------- |
| |
| What: The ieee80211_regdom module parameter |
| When: March 2010 / desktop catchup |
| |
| Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code, |
| and currently serves as an option for users to define an |
| ISO / IEC 3166 alpha2 code for the country they are currently |
| present in. Although there are userspace API replacements for this |
| through nl80211 distributions haven't yet caught up with implementing |
| decent alternatives through standard GUIs. Although available as an |
| option through iw or wpa_supplicant its just a matter of time before |
| distributions pick up good GUI options for this. The ideal solution |
| would actually consist of intelligent designs which would do this for |
| the user automatically even when travelling through different countries. |
| Until then we leave this module parameter as a compromise. |
| |
| When userspace improves with reasonable widely-available alternatives for |
| this we will no longer need this module parameter. This entry hopes that |
| by the super-futuristically looking date of "March 2010" we will have |
| such replacements widely available. |
| |
| Who: Luis R. Rodriguez <lrodriguez@atheros.com> |
| |
| --------------------------- |
| |
| What: dev->power.power_state |
| When: July 2007 |
| Why: Broken design for runtime control over driver power states, confusing |
| driver-internal runtime power management with: mechanisms to support |
| system-wide sleep state transitions; event codes that distinguish |
| different phases of swsusp "sleep" transitions; and userspace policy |
| inputs. This framework was never widely used, and most attempts to |
| use it were broken. Drivers should instead be exposing domain-specific |
| interfaces either to kernel or to userspace. |
| Who: Pavel Machek <pavel@ucw.cz> |
| |
| --------------------------- |
| |
| What: sys_sysctl |
| When: September 2010 |
| Option: CONFIG_SYSCTL_SYSCALL |
| Why: The same information is available in a more convenient from |
| /proc/sys, and none of the sysctl variables appear to be |
| important performance wise. |
| |
| Binary sysctls are a long standing source of subtle kernel |
| bugs and security issues. |
| |
| When I looked several months ago all I could find after |
| searching several distributions were 5 user space programs and |
| glibc (which falls back to /proc/sys) using this syscall. |
| |
| The man page for sysctl(2) documents it as unusable for user |
| space programs. |
| |
| sysctl(2) is not generally ABI compatible to a 32bit user |
| space application on a 64bit and a 32bit kernel. |
| |
| For the last several months the policy has been no new binary |
| sysctls and no one has put forward an argument to use them. |
| |
| Binary sysctls issues seem to keep happening appearing so |
| properly deprecating them (with a warning to user space) and a |
| 2 year grace warning period will mean eventually we can kill |
| them and end the pain. |
| |
| In the mean time individual binary sysctls can be dealt with |
| in a piecewise fashion. |
| |
| Who: Eric Biederman <ebiederm@xmission.com> |
| |
| --------------------------- |
| |
| What: /proc/<pid>/oom_adj |
| When: August 2012 |
| Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's |
| badness heuristic used to determine which task to kill when the kernel |
| is out of memory. |
| |
| The badness heuristic has since been rewritten since the introduction of |
| this tunable such that its meaning is deprecated. The value was |
| implemented as a bitshift on a score generated by the badness() |
| function that did not have any precise units of measure. With the |
| rewrite, the score is given as a proportion of available memory to the |
| task allocating pages, so using a bitshift which grows the score |
| exponentially is, thus, impossible to tune with fine granularity. |
| |
| A much more powerful interface, /proc/<pid>/oom_score_adj, was |
| introduced with the oom killer rewrite that allows users to increase or |
| decrease the badness score linearly. This interface will replace |
| /proc/<pid>/oom_adj. |
| |
| A warning will be emitted to the kernel log if an application uses this |
| deprecated interface. After it is printed once, future warnings will be |
| suppressed until the kernel is rebooted. |
| |
| --------------------------- |
| |
| What: remove EXPORT_SYMBOL(kernel_thread) |
| When: August 2006 |
| Files: arch/*/kernel/*_ksyms.c |
| Check: kernel_thread |
| Why: kernel_thread is a low-level implementation detail. Drivers should |
| use the <linux/kthread.h> API instead which shields them from |
| implementation details and provides a higherlevel interface that |
| prevents bugs and code duplication |
| Who: Christoph Hellwig <hch@lst.de> |
| |
| --------------------------- |
| |
| What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports |
| (temporary transition config option provided until then) |
| The transition config option will also be removed at the same time. |
| When: before 2.6.19 |
| Why: Unused symbols are both increasing the size of the kernel binary |
| and are often a sign of "wrong API" |
| Who: Arjan van de Ven <arjan@linux.intel.com> |
| |
| --------------------------- |
| |
| What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment |
| When: October 2008 |
| Why: The stacking of class devices makes these values misleading and |
| inconsistent. |
| Class devices should not carry any of these properties, and bus |
| devices have SUBSYTEM and DRIVER as a replacement. |
| Who: Kay Sievers <kay.sievers@suse.de> |
| |
| --------------------------- |
| |
| What: ACPI procfs interface |
| When: July 2008 |
| Why: ACPI sysfs conversion should be finished by January 2008. |
| ACPI procfs interface will be removed in July 2008 so that |
| there is enough time for the user space to catch up. |
| Who: Zhang Rui <rui.zhang@intel.com> |
| |
| --------------------------- |
| |
| What: CONFIG_ACPI_PROCFS_POWER |
| When: 2.6.39 |
| Why: sysfs I/F for ACPI power devices, including AC and Battery, |
| has been working in upstream kernel since 2.6.24, Sep 2007. |
| In 2.6.37, we make the sysfs I/F always built in and this option |
| disabled by default. |
| Remove this option and the ACPI power procfs interface in 2.6.39. |
| Who: Zhang Rui <rui.zhang@intel.com> |
| |
| --------------------------- |
| |
| What: /proc/acpi/event |
| When: February 2008 |
| Why: /proc/acpi/event has been replaced by events via the input layer |
| and netlink since 2.6.23. |
| Who: Len Brown <len.brown@intel.com> |
| |
| --------------------------- |
| |
| What: i386/x86_64 bzImage symlinks |
| When: April 2010 |
| |
| Why: The i386/x86_64 merge provides a symlink to the old bzImage |
| location so not yet updated user space tools, e.g. package |
| scripts, do not break. |
| Who: Thomas Gleixner <tglx@linutronix.de> |
| |
| --------------------------- |
| |
| What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib |
| When: February 2010 |
| Why: All callers should use explicit gpio_request()/gpio_free(). |
| The autorequest mechanism in gpiolib was provided mostly as a |
| migration aid for legacy GPIO interfaces (for SOC based GPIOs). |
| Those users have now largely migrated. Platforms implementing |
| the GPIO interfaces without using gpiolib will see no changes. |
| Who: David Brownell <dbrownell@users.sourceforge.net> |
| --------------------------- |
| |
| What: b43 support for firmware revision < 410 |
| When: The schedule was July 2008, but it was decided that we are going to keep the |
| code as long as there are no major maintanance headaches. |
| So it _could_ be removed _any_ time now, if it conflicts with something new. |
| Why: The support code for the old firmware hurts code readability/maintainability |
| and slightly hurts runtime performance. Bugfixes for the old firmware |
| are not provided by Broadcom anymore. |
| Who: Michael Buesch <m@bues.ch> |
| |
| --------------------------- |
| |
| What: Ability for non root users to shm_get hugetlb pages based on mlock |
| resource limits |
| When: 2.6.31 |
| Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or |
| have CAP_IPC_LOCK to be able to allocate shm segments backed by |
| huge pages. The mlock based rlimit check to allow shm hugetlb is |
| inconsistent with mmap based allocations. Hence it is being |
| deprecated. |
| Who: Ravikiran Thirumalai <kiran@scalex86.org> |
| |
| --------------------------- |
| |
| What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS |
| (in net/core/net-sysfs.c) |
| When: After the only user (hal) has seen a release with the patches |
| for enough time, probably some time in 2010. |
| Why: Over 1K .text/.data size reduction, data is available in other |
| ways (ioctls) |
| Who: Johannes Berg <johannes@sipsolutions.net> |
| |
| --------------------------- |
| |
| What: sysfs ui for changing p4-clockmod parameters |
| When: September 2009 |
| Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and |
| e088e4c9cdb618675874becb91b2fd581ee707e6. |
| Removal is subject to fixing any remaining bugs in ACPI which may |
| cause the thermal throttling not to happen at the right time. |
| Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com> |
| |
| ----------------------------- |
| |
| What: fakephp and associated sysfs files in /sys/bus/pci/slots/ |
| When: 2011 |
| Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to |
| represent a machine's physical PCI slots. The change in semantics |
| had userspace implications, as the hotplug core no longer allowed |
| drivers to create multiple sysfs files per physical slot (required |
| for multi-function devices, e.g.). fakephp was seen as a developer's |
| tool only, and its interface changed. Too late, we learned that |
| there were some users of the fakephp interface. |
| |
| In 2.6.30, the original fakephp interface was restored. At the same |
| time, the PCI core gained the ability that fakephp provided, namely |
| function-level hot-remove and hot-add. |
| |
| Since the PCI core now provides the same functionality, exposed in: |
| |
| /sys/bus/pci/rescan |
| /sys/bus/pci/devices/.../remove |
| /sys/bus/pci/devices/.../rescan |
| |
| there is no functional reason to maintain fakephp as well. |
| |
| We will keep the existing module so that 'modprobe fakephp' will |
| present the old /sys/bus/pci/slots/... interface for compatibility, |
| but users are urged to migrate their applications to the API above. |
| |
| After a reasonable transition period, we will remove the legacy |
| fakephp interface. |
| Who: Alex Chiang <achiang@hp.com> |
| |
| --------------------------- |
| |
| What: CONFIG_RFKILL_INPUT |
| When: 2.6.33 |
| Why: Should be implemented in userspace, policy daemon. |
| Who: Johannes Berg <johannes@sipsolutions.net> |
| |
| ---------------------------- |
| |
| What: sound-slot/service-* module aliases and related clutters in |
| sound/sound_core.c |
| When: August 2010 |
| Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR |
| (14) and requests modules using custom sound-slot/service-* |
| module aliases. The only benefit of doing this is allowing |
| use of custom module aliases which might as well be considered |
| a bug at this point. This preemptive claiming prevents |
| alternative OSS implementations. |
| |
| Till the feature is removed, the kernel will be requesting |
| both sound-slot/service-* and the standard char-major-* module |
| aliases and allow turning off the pre-claiming selectively via |
| CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss |
| kernel parameter. |
| |
| After the transition phase is complete, both the custom module |
| aliases and switches to disable it will go away. This removal |
| will also allow making ALSA OSS emulation independent of |
| sound_core. The dependency will be broken then too. |
| Who: Tejun Heo <tj@kernel.org> |
| |
| ---------------------------- |
| |
| What: sysfs-class-rfkill state file |
| When: Feb 2014 |
| Files: net/rfkill/core.c |
| Why: Documented as obsolete since Feb 2010. This file is limited to 3 |
| states while the rfkill drivers can have 4 states. |
| Who: anybody or Florian Mickler <florian@mickler.org> |
| |
| ---------------------------- |
| |
| What: sysfs-class-rfkill claim file |
| When: Feb 2012 |
| Files: net/rfkill/core.c |
| Why: It is not possible to claim an rfkill driver since 2007. This is |
| Documented as obsolete since Feb 2010. |
| Who: anybody or Florian Mickler <florian@mickler.org> |
| |
| ---------------------------- |
| |
| What: KVM paravirt mmu host support |
| When: January 2011 |
| Why: The paravirt mmu host support is slower than non-paravirt mmu, both |
| on newer and older hardware. It is already not exposed to the guest, |
| and kept only for live migration purposes. |
| Who: Avi Kivity <avi@redhat.com> |
| |
| ---------------------------- |
| |
| What: iwlwifi 50XX module parameters |
| When: 3.0 |
| Why: The "..50" modules parameters were used to configure 5000 series and |
| up devices; different set of module parameters also available for 4965 |
| with same functionalities. Consolidate both set into single place |
| in drivers/net/wireless/iwlwifi/iwl-agn.c |
| |
| Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> |
| |
| ---------------------------- |
| |
| What: iwl4965 alias support |
| When: 3.0 |
| Why: Internal alias support has been present in module-init-tools for some |
| time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed |
| with no impact. |
| |
| Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> |
| |
| --------------------------- |
| |
| What: xt_NOTRACK |
| Files: net/netfilter/xt_NOTRACK.c |
| When: April 2011 |
| Why: Superseded by xt_CT |
| Who: Netfilter developer team <netfilter-devel@vger.kernel.org> |
| |
| ---------------------------- |
| |
| What: IRQF_DISABLED |
| When: 2.6.36 |
| Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled |
| Who: Thomas Gleixner <tglx@linutronix.de> |
| |
| ---------------------------- |
| |
| What: PCI DMA unmap state API |
| When: August 2012 |
| Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced |
| with DMA unmap state API (DMA unmap state API can be used for |
| any bus). |
| Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> |
| |
| ---------------------------- |
| |
| What: iwlwifi disable_hw_scan module parameters |
| When: 3.0 |
| Why: Hareware scan is the prefer method for iwlwifi devices for |
| scanning operation. Remove software scan support for all the |
| iwlwifi devices. |
| |
| Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> |
| |
| ---------------------------- |
| |
| What: Legacy, non-standard chassis intrusion detection interface. |
| When: June 2011 |
| Why: The adm9240, w83792d and w83793 hardware monitoring drivers have |
| legacy interfaces for chassis intrusion detection. A standard |
| interface has been added to each driver, so the legacy interface |
| can be removed. |
| Who: Jean Delvare <khali@linux-fr.org> |
| |
| ---------------------------- |
| |
| What: xt_connlimit rev 0 |
| When: 2012 |
| Who: Jan Engelhardt <jengelh@medozas.de> |
| Files: net/netfilter/xt_connlimit.c |
| |
| ---------------------------- |
| |
| What: ipt_addrtype match include file |
| When: 2012 |
| Why: superseded by xt_addrtype |
| Who: Florian Westphal <fw@strlen.de> |
| Files: include/linux/netfilter_ipv4/ipt_addrtype.h |
| |
| ---------------------------- |
| |
| What: i2c_driver.attach_adapter |
| i2c_driver.detach_adapter |
| When: September 2011 |
| Why: These legacy callbacks should no longer be used as i2c-core offers |
| a variety of preferable alternative ways to instantiate I2C devices. |
| Who: Jean Delvare <khali@linux-fr.org> |
| |
| ---------------------------- |
| |
| What: Support for UVCIOC_CTRL_ADD in the uvcvideo driver |
| When: 3.2 |
| Why: The information passed to the driver by this ioctl is now queried |
| dynamically from the device. |
| Who: Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
| |
| ---------------------------- |
| |
| What: Support for UVCIOC_CTRL_MAP_OLD in the uvcvideo driver |
| When: 3.2 |
| Why: Used only by applications compiled against older driver versions. |
| Superseded by UVCIOC_CTRL_MAP which supports V4L2 menu controls. |
| Who: Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
| |
| ---------------------------- |
| |
| What: Support for UVCIOC_CTRL_GET and UVCIOC_CTRL_SET in the uvcvideo driver |
| When: 3.2 |
| Why: Superseded by the UVCIOC_CTRL_QUERY ioctl. |
| Who: Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
| |
| ---------------------------- |
| |
| What: Support for driver specific ioctls in the pwc driver (everything |
| defined in media/pwc-ioctl.h) |
| When: 3.3 |
| Why: This stems from the v4l1 era, with v4l2 everything can be done with |
| standardized v4l2 API calls |
| Who: Hans de Goede <hdegoede@redhat.com> |
| |
| ---------------------------- |
| |
| What: Driver specific sysfs API in the pwc driver |
| When: 3.3 |
| Why: Setting pan/tilt should be done with v4l2 controls, like with other |
| cams. The button is available as a standard input device |
| Who: Hans de Goede <hdegoede@redhat.com> |
| |
| ---------------------------- |
| |
| What: Driver specific use of pixfmt.priv in the pwc driver |
| When: 3.3 |
| Why: The .priv field never was intended for this, setting a framerate is |
| support using the standardized S_PARM ioctl |
| Who: Hans de Goede <hdegoede@redhat.com> |
| |
| ---------------------------- |
| |
| What: Software emulation of arbritary resolutions in the pwc driver |
| When: 3.3 |
| Why: The pwc driver claims to support any resolution between 160x120 |
| and 640x480, but emulates this by simply drawing a black border |
| around the image. Userspace can draw its own black border if it |
| really wants one. |
| Who: Hans de Goede <hdegoede@redhat.com> |
| |
| ---------------------------- |
| |
| What: For VIDIOC_S_FREQUENCY the type field must match the device node's type. |
| If not, return -EINVAL. |
| When: 3.2 |
| Why: It makes no sense to switch the tuner to radio mode by calling |
| VIDIOC_S_FREQUENCY on a video node, or to switch the tuner to tv mode by |
| calling VIDIOC_S_FREQUENCY on a radio node. This is the first step of a |
| move to more consistent handling of tv and radio tuners. |
| Who: Hans Verkuil <hans.verkuil@cisco.com> |
| |
| ---------------------------- |
| |
| What: Opening a radio device node will no longer automatically switch the |
| tuner mode from tv to radio. |
| When: 3.3 |
| Why: Just opening a V4L device should not change the state of the hardware |
| like that. It's very unexpected and against the V4L spec. Instead, you |
| switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second |
| and last step of the move to consistent handling of tv and radio tuners. |
| Who: Hans Verkuil <hans.verkuil@cisco.com> |
| |
| ---------------------------- |
| |
| What: g_file_storage driver |
| When: 3.8 |
| Why: This driver has been superseded by g_mass_storage. |
| Who: Alan Stern <stern@rowland.harvard.edu> |
| |
| ---------------------------- |
