Documentation/feature-removal-schedule.txt

   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.  The suggested deprecation period is 3 releases.
   6
   7 ---------------------------
   8
   9 What:   ddebug_query="query" boot cmdline param
  10 When:   v3.8
  11 Why:    obsoleted by dyndbg="query" and module.dyndbg="query"
  12 Who:    Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com>
  13
  14 ---------------------------
  15
  16 What:   CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
  17 When:   2012
  18 Why:    This optional sub-feature of APM is of dubious reliability,
  19         and ancient APM laptops are likely better served by calling HLT.
  20         Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
  21         the pm_idle function pointer to modules.
  22 Who:    Len Brown <len.brown@intel.com>
  23
  24 ----------------------------
  25
  26 What:   x86_32 "no-hlt" cmdline param
  27 When:   2012
  28 Why:    remove a branch from idle path, simplify code used by everybody.
  29         This option disabled the use of HLT in idle and machine_halt()
  30         for hardware that was flakey 15-years ago.  Today we have
  31         "idle=poll" that removed HLT from idle, and so if such a machine
  32         is still running the upstream kernel, "idle=poll" is likely sufficient.
  33 Who:    Len Brown <len.brown@intel.com>
  34
  35 ----------------------------
  36
  37 What:   x86 "idle=mwait" cmdline param
  38 When:   2012
  39 Why:    simplify x86 idle code
  40 Who:    Len Brown <len.brown@intel.com>
  41
  42 ----------------------------
  43
  44 What:   PRISM54
  45 When:   2.6.34
  46
  47 Why:    prism54 FullMAC PCI / Cardbus devices used to be supported only by the
  48         prism54 wireless driver. After Intersil stopped selling these
  49         devices in preference for the newer more flexible SoftMAC devices
  50         a SoftMAC device driver was required and prism54 did not support
  51         them. The p54pci driver now exists and has been present in the kernel for
  52         a while. This driver supports both SoftMAC devices and FullMAC devices.
  53         The main difference between these devices was the amount of memory which
  54         could be used for the firmware. The SoftMAC devices support a smaller
  55         amount of memory. Because of this the SoftMAC firmware fits into FullMAC
  56         devices's memory. p54pci supports not only PCI / Cardbus but also USB
  57         and SPI. Since p54pci supports all devices prism54 supports
  58         you will have a conflict. I'm not quite sure how distributions are
  59         handling this conflict right now. prism54 was kept around due to
  60         claims users may experience issues when using the SoftMAC driver.
  61         Time has passed users have not reported issues. If you use prism54
  62         and for whatever reason you cannot use p54pci please let us know!
  63         E-mail us at: linux-wireless@vger.kernel.org
  64
  65         For more information see the p54 wiki page:
  66
  67         http://wireless.kernel.org/en/users/Drivers/p54
  68
  69 Who:    Luis R. Rodriguez <lrodriguez@atheros.com>
  70
  71 ---------------------------
  72
  73 What:   IRQF_SAMPLE_RANDOM
  74 Check:  IRQF_SAMPLE_RANDOM
  75 When:   July 2009
  76
  77 Why:    Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy
  78         sources in the kernel's current entropy model. To resolve this, every
  79         input point to the kernel's entropy pool needs to better document the
  80         type of entropy source it actually is. This will be replaced with
  81         additional add_*_randomness functions in drivers/char/random.c
  82
  83 Who:    Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com>
  84
  85 ---------------------------
  86
  87 What:   The ieee80211_regdom module parameter
  88 When:   March 2010 / desktop catchup
  89
  90 Why:    This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
  91         and currently serves as an option for users to define an
  92         ISO / IEC 3166 alpha2 code for the country they are currently
  93         present in. Although there are userspace API replacements for this
  94         through nl80211 distributions haven't yet caught up with implementing
  95         decent alternatives through standard GUIs. Although available as an
  96         option through iw or wpa_supplicant its just a matter of time before
  97         distributions pick up good GUI options for this. The ideal solution
  98         would actually consist of intelligent designs which would do this for
  99         the user automatically even when travelling through different countries.
 100         Until then we leave this module parameter as a compromise.
 101
 102         When userspace improves with reasonable widely-available alternatives for
 103         this we will no longer need this module parameter. This entry hopes that
 104         by the super-futuristically looking date of "March 2010" we will have
 105         such replacements widely available.
 106
 107 Who:    Luis R. Rodriguez <lrodriguez@atheros.com>
 108
 109 ---------------------------
 110
 111 What:   dev->power.power_state
 112 When:   July 2007
 113 Why:    Broken design for runtime control over driver power states, confusing
 114         driver-internal runtime power management with:  mechanisms to support
 115         system-wide sleep state transitions; event codes that distinguish
 116         different phases of swsusp "sleep" transitions; and userspace policy
 117         inputs.  This framework was never widely used, and most attempts to
 118         use it were broken.  Drivers should instead be exposing domain-specific
 119         interfaces either to kernel or to userspace.
 120 Who:    Pavel Machek <pavel@ucw.cz>
 121
 122 ---------------------------
 123
 124 What:   /proc/<pid>/oom_adj
 125 When:   August 2012
 126 Why:    /proc/<pid>/oom_adj allows userspace to influence the oom killer's
 127         badness heuristic used to determine which task to kill when the kernel
 128         is out of memory.
 129
 130         The badness heuristic has since been rewritten since the introduction of
 131         this tunable such that its meaning is deprecated.  The value was
 132         implemented as a bitshift on a score generated by the badness()
 133         function that did not have any precise units of measure.  With the
 134         rewrite, the score is given as a proportion of available memory to the
 135         task allocating pages, so using a bitshift which grows the score
 136         exponentially is, thus, impossible to tune with fine granularity.
 137
 138         A much more powerful interface, /proc/<pid>/oom_score_adj, was
 139         introduced with the oom killer rewrite that allows users to increase or
 140         decrease the badness score linearly.  This interface will replace
 141         /proc/<pid>/oom_adj.
 142
 143         A warning will be emitted to the kernel log if an application uses this
 144         deprecated interface.  After it is printed once, future warnings will be
 145         suppressed until the kernel is rebooted.
 146
 147 ---------------------------
 148
 149 What:   remove EXPORT_SYMBOL(kernel_thread)
 150 When:   August 2006
 151 Files:  arch/*/kernel/*_ksyms.c
 152 Check:  kernel_thread
 153 Why:    kernel_thread is a low-level implementation detail.  Drivers should
 154         use the <linux/kthread.h> API instead which shields them from
 155         implementation details and provides a higherlevel interface that
 156         prevents bugs and code duplication
 157 Who:    Christoph Hellwig <hch@lst.de>
 158
 159 ---------------------------
 160
 161 What:   Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
 162         (temporary transition config option provided until then)
 163         The transition config option will also be removed at the same time.
 164 When:   before 2.6.19
 165 Why:    Unused symbols are both increasing the size of the kernel binary
 166         and are often a sign of "wrong API"
 167 Who:    Arjan van de Ven <arjan@linux.intel.com>
 168
 169 ---------------------------
 170
 171 What:   PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
 172 When:   October 2008
 173 Why:    The stacking of class devices makes these values misleading and
 174         inconsistent.
 175         Class devices should not carry any of these properties, and bus
 176         devices have SUBSYTEM and DRIVER as a replacement.
 177 Who:    Kay Sievers <kay.sievers@suse.de>
 178
 179 ---------------------------
 180
 181 What:   ACPI procfs interface
 182 When:   July 2008
 183 Why:    ACPI sysfs conversion should be finished by January 2008.
 184         ACPI procfs interface will be removed in July 2008 so that
 185         there is enough time for the user space to catch up.
 186 Who:    Zhang Rui <rui.zhang@intel.com>
 187
 188 ---------------------------
 189
 190 What:   CONFIG_ACPI_PROCFS_POWER
 191 When:   2.6.39
 192 Why:    sysfs I/F for ACPI power devices, including AC and Battery,
 193         has been working in upstream kernel since 2.6.24, Sep 2007.
 194         In 2.6.37, we make the sysfs I/F always built in and this option
 195         disabled by default.
 196         Remove this option and the ACPI power procfs interface in 2.6.39.
 197 Who:    Zhang Rui <rui.zhang@intel.com>
 198
 199 ---------------------------
 200
 201 What:   /proc/acpi/event
 202 When:   February 2008
 203 Why:    /proc/acpi/event has been replaced by events via the input layer
 204         and netlink since 2.6.23.
 205 Who:    Len Brown <len.brown@intel.com>
 206
 207 ---------------------------
 208
 209 What:   i386/x86_64 bzImage symlinks
 210 When:   April 2010
 211
 212 Why:    The i386/x86_64 merge provides a symlink to the old bzImage
 213         location so not yet updated user space tools, e.g. package
 214         scripts, do not break.
 215 Who:    Thomas Gleixner <tglx@linutronix.de>
 216
 217 ---------------------------
 218
 219 What:   GPIO autorequest on gpio_direction_{input,output}() in gpiolib
 220 When:   February 2010
 221 Why:    All callers should use explicit gpio_request()/gpio_free().
 222         The autorequest mechanism in gpiolib was provided mostly as a
 223         migration aid for legacy GPIO interfaces (for SOC based GPIOs).
 224         Those users have now largely migrated.  Platforms implementing
 225         the GPIO interfaces without using gpiolib will see no changes.
 226 Who:    David Brownell <dbrownell@users.sourceforge.net>
 227 ---------------------------
 228
 229 What:   b43 support for firmware revision < 410
 230 When:   The schedule was July 2008, but it was decided that we are going to keep the
 231         code as long as there are no major maintanance headaches.
 232         So it _could_ be removed _any_ time now, if it conflicts with something new.
 233 Why:    The support code for the old firmware hurts code readability/maintainability
 234         and slightly hurts runtime performance. Bugfixes for the old firmware
 235         are not provided by Broadcom anymore.
 236 Who:    Michael Buesch <m@bues.ch>
 237
 238 ---------------------------
 239
 240 What:   Ability for non root users to shm_get hugetlb pages based on mlock
 241         resource limits
 242 When:   2.6.31
 243 Why:    Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
 244         have CAP_IPC_LOCK to be able to allocate shm segments backed by
 245         huge pages.  The mlock based rlimit check to allow shm hugetlb is
 246         inconsistent with mmap based allocations.  Hence it is being
 247         deprecated.
 248 Who:    Ravikiran Thirumalai <kiran@scalex86.org>
 249
 250 ---------------------------
 251
 252 What:   sysfs ui for changing p4-clockmod parameters
 253 When:   September 2009
 254 Why:    See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
 255         e088e4c9cdb618675874becb91b2fd581ee707e6.
 256         Removal is subject to fixing any remaining bugs in ACPI which may
 257         cause the thermal throttling not to happen at the right time.
 258 Who:    Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
 259
 260 -----------------------------
 261
 262 What:   fakephp and associated sysfs files in /sys/bus/pci/slots/
 263 When:   2011
 264 Why:    In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
 265         represent a machine's physical PCI slots. The change in semantics
 266         had userspace implications, as the hotplug core no longer allowed
 267         drivers to create multiple sysfs files per physical slot (required
 268         for multi-function devices, e.g.). fakephp was seen as a developer's
 269         tool only, and its interface changed. Too late, we learned that
 270         there were some users of the fakephp interface.
 271
 272         In 2.6.30, the original fakephp interface was restored. At the same
 273         time, the PCI core gained the ability that fakephp provided, namely
 274         function-level hot-remove and hot-add.
 275
 276         Since the PCI core now provides the same functionality, exposed in:
 277
 278                 /sys/bus/pci/rescan
 279                 /sys/bus/pci/devices/.../remove
 280                 /sys/bus/pci/devices/.../rescan
 281
 282         there is no functional reason to maintain fakephp as well.
 283
 284         We will keep the existing module so that 'modprobe fakephp' will
 285         present the old /sys/bus/pci/slots/... interface for compatibility,
 286         but users are urged to migrate their applications to the API above.
 287
 288         After a reasonable transition period, we will remove the legacy
 289         fakephp interface.
 290 Who:    Alex Chiang <achiang@hp.com>
 291
 292 ---------------------------
 293
 294 What:   CONFIG_RFKILL_INPUT
 295 When:   2.6.33
 296 Why:    Should be implemented in userspace, policy daemon.
 297 Who:    Johannes Berg <johannes@sipsolutions.net>
 298
 299 ----------------------------
 300
 301 What:   sound-slot/service-* module aliases and related clutters in
 302         sound/sound_core.c
 303 When:   August 2010
 304 Why:    OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
 305         (14) and requests modules using custom sound-slot/service-*
 306         module aliases.  The only benefit of doing this is allowing
 307         use of custom module aliases which might as well be considered
 308         a bug at this point.  This preemptive claiming prevents
 309         alternative OSS implementations.
 310
 311         Till the feature is removed, the kernel will be requesting
 312         both sound-slot/service-* and the standard char-major-* module
 313         aliases and allow turning off the pre-claiming selectively via
 314         CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
 315         kernel parameter.
 316
 317         After the transition phase is complete, both the custom module
 318         aliases and switches to disable it will go away.  This removal
 319         will also allow making ALSA OSS emulation independent of
 320         sound_core.  The dependency will be broken then too.
 321 Who:    Tejun Heo <tj@kernel.org>
 322
 323 ----------------------------
 324
 325 What:   sysfs-class-rfkill state file
 326 When:   Feb 2014
 327 Files:  net/rfkill/core.c
 328 Why:    Documented as obsolete since Feb 2010. This file is limited to 3
 329         states while the rfkill drivers can have 4 states.
 330 Who:    anybody or Florian Mickler <florian@mickler.org>
 331
 332 ----------------------------
 333
 334 What:   sysfs-class-rfkill claim file
 335 When:   Feb 2012
 336 Files:  net/rfkill/core.c
 337 Why:    It is not possible to claim an rfkill driver since 2007. This is
 338         Documented as obsolete since Feb 2010.
 339 Who:    anybody or Florian Mickler <florian@mickler.org>
 340
 341 ----------------------------
 342
 343 What:   iwlwifi 50XX module parameters
 344 When:   3.0
 345 Why:    The "..50" modules parameters were used to configure 5000 series and
 346         up devices; different set of module parameters also available for 4965
 347         with same functionalities. Consolidate both set into single place
 348         in drivers/net/wireless/iwlwifi/iwl-agn.c
 349
 350 Who:    Wey-Yi Guy <wey-yi.w.guy@intel.com>
 351
 352 ----------------------------
 353
 354 What:   iwl4965 alias support
 355 When:   3.0
 356 Why:    Internal alias support has been present in module-init-tools for some
 357         time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
 358         with no impact.
 359
 360 Who:    Wey-Yi Guy <wey-yi.w.guy@intel.com>
 361
 362 ---------------------------
 363
 364 What:   xt_NOTRACK
 365 Files:  net/netfilter/xt_NOTRACK.c
 366 When:   April 2011
 367 Why:    Superseded by xt_CT
 368 Who:    Netfilter developer team <netfilter-devel@vger.kernel.org>
 369
 370 ----------------------------
 371
 372 What:   IRQF_DISABLED
 373 When:   2.6.36
 374 Why:    The flag is a NOOP as we run interrupt handlers with interrupts disabled
 375 Who:    Thomas Gleixner <tglx@linutronix.de>
 376
 377 ----------------------------
 378
 379 What:   PCI DMA unmap state API
 380 When:   August 2012
 381 Why:    PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
 382         with DMA unmap state API (DMA unmap state API can be used for
 383         any bus).
 384 Who:    FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
 385
 386 ----------------------------
 387
 388 What:   iwlwifi disable_hw_scan module parameters
 389 When:   3.0
 390 Why:    Hareware scan is the prefer method for iwlwifi devices for
 391         scanning operation. Remove software scan support for all the
 392         iwlwifi devices.
 393
 394 Who:    Wey-Yi Guy <wey-yi.w.guy@intel.com>
 395
 396 ----------------------------
 397
 398 What:   Legacy, non-standard chassis intrusion detection interface.
 399 When:   June 2011
 400 Why:    The adm9240, w83792d and w83793 hardware monitoring drivers have
 401         legacy interfaces for chassis intrusion detection. A standard
 402         interface has been added to each driver, so the legacy interface
 403         can be removed.
 404 Who:    Jean Delvare <khali@linux-fr.org>
 405
 406 ----------------------------
 407
 408 What:   i2c_driver.attach_adapter
 409         i2c_driver.detach_adapter
 410 When:   September 2011
 411 Why:    These legacy callbacks should no longer be used as i2c-core offers
 412         a variety of preferable alternative ways to instantiate I2C devices.
 413 Who:    Jean Delvare <khali@linux-fr.org>
 414
 415 ----------------------------
 416
 417 What:   Opening a radio device node will no longer automatically switch the
 418         tuner mode from tv to radio.
 419 When:   3.3
 420 Why:    Just opening a V4L device should not change the state of the hardware
 421         like that. It's very unexpected and against the V4L spec. Instead, you
 422         switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second
 423         and last step of the move to consistent handling of tv and radio tuners.
 424 Who:    Hans Verkuil <hans.verkuil@cisco.com>
 425
 426 ----------------------------
 427
 428 What:   CONFIG_CFG80211_WEXT
 429 When:   as soon as distributions ship new wireless tools, ie. wpa_supplicant 1.0
 430         and NetworkManager/connman/etc. that are able to use nl80211
 431 Why:    Wireless extensions are deprecated, and userland tools are moving to
 432         using nl80211. New drivers are no longer using wireless extensions,
 433         and while there might still be old drivers, both new drivers and new
 434         userland no longer needs them and they can't be used for an feature
 435         developed in the past couple of years. As such, compatibility with
 436         wireless extensions in new drivers will be removed.
 437 Who:    Johannes Berg <johannes@sipsolutions.net>
 438
 439 ----------------------------
 440
 441 What:   g_file_storage driver
 442 When:   3.8
 443 Why:    This driver has been superseded by g_mass_storage.
 444 Who:    Alan Stern <stern@rowland.harvard.edu>
 445
 446 ----------------------------
 447
 448 What:   threeg and interface sysfs files in /sys/devices/platform/acer-wmi
 449 When:   2012
 450 Why:    In 3.0, we can now autodetect internal 3G device and already have
 451         the threeg rfkill device. So, we plan to remove threeg sysfs support
 452         for it's no longer necessary.
 453
 454         We also plan to remove interface sysfs file that exposed which ACPI-WMI
 455         interface that was used by acer-wmi driver. It will replaced by
 456         information log when acer-wmi initial.
 457 Who:    Lee, Chun-Yi <jlee@novell.com>
 458
 459 ---------------------------
 460
 461 What:   /sys/devices/platform/_UDC_/udc/_UDC_/is_dualspeed file and
 462         is_dualspeed line in /sys/devices/platform/ci13xxx_*/udc/device file.
 463 When:   3.8
 464 Why:    The is_dualspeed file is superseded by maximum_speed in the same
 465         directory and is_dualspeed line in device file is superseded by
 466         max_speed line in the same file.
 467
 468         The maximum_speed/max_speed specifies maximum speed supported by UDC.
 469         To check if dualspeeed is supported, check if the value is >= 3.
 470         Various possible speeds are defined in <linux/usb/ch9.h>.
 471 Who:    Michal Nazarewicz <mina86@mina86.com>
 472
 473 ----------------------------
 474
 475 What:   The XFS nodelaylog mount option
 476 When:   3.3
 477 Why:    The delaylog mode that has been the default since 2.6.39 has proven
 478         stable, and the old code is in the way of additional improvements in
 479         the log code.
 480 Who:    Christoph Hellwig <hch@lst.de>
 481
 482 ----------------------------
 483
 484 What:   iwlagn alias support
 485 When:   3.5
 486 Why:    The iwlagn module has been renamed iwlwifi.  The alias will be around
 487         for backward compatibility for several cycles and then dropped.
 488 Who:    Don Fry <donald.h.fry@intel.com>
 489
 490 ----------------------------
 491
 492 What:   pci_scan_bus_parented()
 493 When:   3.5
 494 Why:    The pci_scan_bus_parented() interface creates a new root bus.  The
 495         bus is created with default resources (ioport_resource and
 496         iomem_resource) that are always wrong, so we rely on arch code to
 497         correct them later.  Callers of pci_scan_bus_parented() should
 498         convert to using pci_scan_root_bus() so they can supply a list of
 499         bus resources when the bus is created.
 500 Who:    Bjorn Helgaas <bhelgaas@google.com>
 501
 502 ----------------------------
 503
 504 What:   Low Performance USB Block driver ("CONFIG_BLK_DEV_UB")
 505 When:   3.6
 506 Why:    This driver provides support for USB storage devices like "USB
 507         sticks". As of now, it is deactivated in Debian, Fedora and
 508         Ubuntu. All current users can switch over to usb-storage
 509         (CONFIG_USB_STORAGE) which only drawback is the additional SCSI
 510         stack.
 511 Who:    Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
 512
 513 ----------------------------
 514
 515 What:   kmap_atomic(page, km_type)
 516 When:   3.5
 517 Why:    The old kmap_atomic() with two arguments is deprecated, we only
 518         keep it for backward compatibility for few cycles and then drop it.
 519 Who:    Cong Wang <amwang@redhat.com>
 520
 521 ----------------------------
 522
 523 What:   get_robust_list syscall
 524 When:   2013
 525 Why:    There appear to be no production users of the get_robust_list syscall,
 526         and it runs the risk of leaking address locations, allowing the bypass
 527         of ASLR. It was only ever intended for debugging, so it should be
 528         removed.
 529 Who:    Kees Cook <keescook@chromium.org>
 530
 531 ----------------------------
 532
 533 What:   Removing the pn544 raw driver.
 534 When:   3.6
 535 Why:    With the introduction of the NFC HCI and SHDL kernel layers, pn544.c
 536         is being replaced by pn544_hci.c which is accessible through the netlink
 537         and socket NFC APIs. Moreover, pn544.c is outdated and does not seem to
 538         work properly with the latest Android stacks.
 539         Having 2 drivers for the same hardware is confusing and as such we
 540         should only keep the one following the kernel NFC APIs.
 541 Who:    Samuel Ortiz <sameo@linux.intel.com>
 542
 543 ----------------------------
 544
 545 What:   setitimer accepts user NULL pointer (value)
 546 When:   3.6
 547 Why:    setitimer is not returning -EFAULT if user pointer is NULL. This
 548         violates the spec.
 549 Who:    Sasikantha Babu <sasikanth.v19@gmail.com>
 550
 551 ----------------------------
 552
 553 What:   remove bogus DV presets V4L2_DV_1080I29_97, V4L2_DV_1080I30 and
 554         V4L2_DV_1080I25
 555 When:   3.6
 556 Why:    These HDTV formats do not exist and were added by a confused mind
 557         (that was me, to be precise...)
 558 Who:    Hans Verkuil <hans.verkuil@cisco.com>
 559
 560 ----------------------------
 561
 562 What:   V4L2_CID_HCENTER, V4L2_CID_VCENTER V4L2 controls
 563 When:   3.7
 564 Why:    The V4L2_CID_VCENTER, V4L2_CID_HCENTER controls have been deprecated
 565         for about 4 years and they are not used by any mainline driver.
 566         There are newer controls (V4L2_CID_PAN*, V4L2_CID_TILT*) that provide
 567         similar functionality.
 568 Who:    Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
 569
 570 ----------------------------
 571
 572 What:   cgroup option updates via remount
 573 When:   March 2013
 574 Why:    Remount currently allows changing bound subsystems and
 575         release_agent.  Rebinding is hardly useful as it only works
 576         when the hierarchy is empty and release_agent itself should be
 577         replaced with conventional fsnotify.
 578
 579 ----------------------------
 580
 581 What:  xt_recent rev 0
 582 When:  2013
 583 Who:   Pablo Neira Ayuso <pablo@netfilter.org>
 584 Files: net/netfilter/xt_recent.c
 585
 586 ----------------------------
 587
 588 What:   KVM debugfs statistics
 589 When:   2013
 590 Why:    KVM tracepoints provide mostly equivalent information in a much more
 591         flexible fashion.
 592
 593 ----------------------------
 594
 595 What:   at91-mci driver ("CONFIG_MMC_AT91")
 596 When:   3.7
 597 Why:    There are two mci drivers: at91-mci and atmel-mci. The PDC support
 598         was added to atmel-mci as a first step to support more chips.
 599         Then at91-mci was kept only for old IP versions (on at91rm9200 and
 600         at91sam9261). The support of these IP versions has just been added
 601         to atmel-mci, so atmel-mci can be used for all chips.
 602 Who:    Ludovic Desroches <ludovic.desroches@atmel.com>
 603
 604 ----------------------------
 605
 606 What:   net/wanrouter/
 607 When:   June 2013
 608 Why:    Unsupported/unmaintained/unused since 2.6
 609
 610 ----------------------------