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.
   6
   7 ---------------------------
   8
   9 What:   old static regulatory information and ieee80211_regdom module parameter
  10 When:   2.6.29
  11 Why:    The old regulatory infrastructure has been replaced with a new one
  12         which does not require statically defined regulatory domains. We do
  13         not want to keep static regulatory domains in the kernel due to the
  14         the dynamic nature of regulatory law and localization. We kept around
  15         the old static definitions for the regulatory domains of:
  16                 * US
  17                 * JP
  18                 * EU
  19         and used by default the US when CONFIG_WIRELESS_OLD_REGULATORY was
  20         set. We also kept around the ieee80211_regdom module parameter in case
  21         some applications were relying on it. Changing regulatory domains
  22         can now be done instead by using nl80211, as is done with iw.
  23 Who:    Luis R. Rodriguez <lrodriguez@atheros.com>
  24
  25 ---------------------------
  26
  27 What:   dev->power.power_state
  28 When:   July 2007
  29 Why:    Broken design for runtime control over driver power states, confusing
  30         driver-internal runtime power management with:  mechanisms to support
  31         system-wide sleep state transitions; event codes that distinguish
  32         different phases of swsusp "sleep" transitions; and userspace policy
  33         inputs.  This framework was never widely used, and most attempts to
  34         use it were broken.  Drivers should instead be exposing domain-specific
  35         interfaces either to kernel or to userspace.
  36 Who:    Pavel Machek <pavel@suse.cz>
  37
  38 ---------------------------
  39
  40 What:   Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  41 When:   December 2008
  42 Files:  include/linux/video_decoder.h include/linux/videodev.h
  43 Check:  include/linux/video_decoder.h include/linux/videodev.h
  44 Why:    V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
  45         series. The old API have lots of drawbacks and don't provide enough
  46         means to work with all video and audio standards. The newer API is
  47         already available on the main drivers and should be used instead.
  48         Newer drivers should use v4l_compat_translate_ioctl function to handle
  49         old calls, replacing to newer ones.
  50         Decoder iocts are using internally to allow video drivers to
  51         communicate with video decoders. This should also be improved to allow
  52         V4L2 calls being translated into compatible internal ioctls.
  53         Compatibility ioctls will be provided, for a while, via
  54         v4l1-compat module.
  55 Who:    Mauro Carvalho Chehab <mchehab@infradead.org>
  56
  57 ---------------------------
  58
  59 What:   PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  60 When:   November 2005
  61 Files:  drivers/pcmcia/: pcmcia_ioctl.c
  62 Why:    With the 16-bit PCMCIA subsystem now behaving (almost) like a
  63         normal hotpluggable bus, and with it using the default kernel
  64         infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  65         control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  66         unnecessary, and makes further cleanups and integration of the
  67         PCMCIA subsystem into the Linux kernel device driver model more
  68         difficult. The features provided by cardmgr and cardctl are either
  69         handled by the kernel itself now or are available in the new
  70         pcmciautils package available at
  71         http://kernel.org/pub/linux/utils/kernel/pcmcia/
  72 Who:    Dominik Brodowski <linux@brodo.de>
  73
  74 ---------------------------
  75
  76 What:   sys_sysctl
  77 When:   September 2010
  78 Option: CONFIG_SYSCTL_SYSCALL
  79 Why:    The same information is available in a more convenient from
  80         /proc/sys, and none of the sysctl variables appear to be
  81         important performance wise.
  82
  83         Binary sysctls are a long standing source of subtle kernel
  84         bugs and security issues.
  85
  86         When I looked several months ago all I could find after
  87         searching several distributions were 5 user space programs and
  88         glibc (which falls back to /proc/sys) using this syscall.
  89
  90         The man page for sysctl(2) documents it as unusable for user
  91         space programs.
  92
  93         sysctl(2) is not generally ABI compatible to a 32bit user
  94         space application on a 64bit and a 32bit kernel.
  95
  96         For the last several months the policy has been no new binary
  97         sysctls and no one has put forward an argument to use them.
  98
  99         Binary sysctls issues seem to keep happening appearing so
 100         properly deprecating them (with a warning to user space) and a
 101         2 year grace warning period will mean eventually we can kill
 102         them and end the pain.
 103
 104         In the mean time individual binary sysctls can be dealt with
 105         in a piecewise fashion.
 106
 107 Who:    Eric Biederman <ebiederm@xmission.com>
 108
 109 ---------------------------
 110
 111 What:   remove EXPORT_SYMBOL(kernel_thread)
 112 When:   August 2006
 113 Files:  arch/*/kernel/*_ksyms.c
 114 Check:  kernel_thread
 115 Why:    kernel_thread is a low-level implementation detail.  Drivers should
 116         use the <linux/kthread.h> API instead which shields them from
 117         implementation details and provides a higherlevel interface that
 118         prevents bugs and code duplication
 119 Who:    Christoph Hellwig <hch@lst.de>
 120
 121 ---------------------------
 122
 123 What:   eepro100 network driver
 124 When:   January 2007
 125 Why:    replaced by the e100 driver
 126 Who:    Adrian Bunk <bunk@stusta.de>
 127
 128 ---------------------------
 129
 130 What:   Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
 131         (temporary transition config option provided until then)
 132         The transition config option will also be removed at the same time.
 133 When:   before 2.6.19
 134 Why:    Unused symbols are both increasing the size of the kernel binary
 135         and are often a sign of "wrong API"
 136 Who:    Arjan van de Ven <arjan@linux.intel.com>
 137
 138 ---------------------------
 139
 140 What:   PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
 141 When:   October 2008
 142 Why:    The stacking of class devices makes these values misleading and
 143         inconsistent.
 144         Class devices should not carry any of these properties, and bus
 145         devices have SUBSYTEM and DRIVER as a replacement.
 146 Who:    Kay Sievers <kay.sievers@suse.de>
 147
 148 ---------------------------
 149
 150 What:   ACPI procfs interface
 151 When:   July 2008
 152 Why:    ACPI sysfs conversion should be finished by January 2008.
 153         ACPI procfs interface will be removed in July 2008 so that
 154         there is enough time for the user space to catch up.
 155 Who:    Zhang Rui <rui.zhang@intel.com>
 156
 157 ---------------------------
 158
 159 What:   /proc/acpi/button
 160 When:   August 2007
 161 Why:    /proc/acpi/button has been replaced by events to the input layer
 162         since 2.6.20.
 163 Who:    Len Brown <len.brown@intel.com>
 164
 165 ---------------------------
 166
 167 What:   /proc/acpi/event
 168 When:   February 2008
 169 Why:    /proc/acpi/event has been replaced by events via the input layer
 170         and netlink since 2.6.23.
 171 Who:    Len Brown <len.brown@intel.com>
 172
 173 ---------------------------
 174
 175 What: libata spindown skipping and warning
 176 When: Dec 2008
 177 Why:  Some halt(8) implementations synchronize caches for and spin
 178       down libata disks because libata didn't use to spin down disk on
 179       system halt (only synchronized caches).
 180       Spin down on system halt is now implemented.  sysfs node
 181       /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
 182       spin down support is available.
 183       Because issuing spin down command to an already spun down disk
 184       makes some disks spin up just to spin down again, libata tracks
 185       device spindown status to skip the extra spindown command and
 186       warn about it.
 187       This is to give userspace tools the time to get updated and will
 188       be removed after userspace is reasonably updated.
 189 Who:  Tejun Heo <htejun@gmail.com>
 190
 191 ---------------------------
 192
 193 What:   i386/x86_64 bzImage symlinks
 194 When:   April 2010
 195
 196 Why:    The i386/x86_64 merge provides a symlink to the old bzImage
 197         location so not yet updated user space tools, e.g. package
 198         scripts, do not break.
 199 Who:    Thomas Gleixner <tglx@linutronix.de>
 200
 201 ---------------------------
 202
 203 What (Why):
 204         - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
 205           (superseded by xt_TOS/xt_tos target & match)
 206
 207         - "forwarding" header files like ipt_mac.h in
 208           include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/
 209
 210         - xt_CONNMARK match revision 0
 211           (superseded by xt_CONNMARK match revision 1)
 212
 213         - xt_MARK target revisions 0 and 1
 214           (superseded by xt_MARK match revision 2)
 215
 216         - xt_connmark match revision 0
 217           (superseded by xt_connmark match revision 1)
 218
 219         - xt_conntrack match revision 0
 220           (superseded by xt_conntrack match revision 1)
 221
 222         - xt_iprange match revision 0,
 223           include/linux/netfilter_ipv4/ipt_iprange.h
 224           (superseded by xt_iprange match revision 1)
 225
 226         - xt_mark match revision 0
 227           (superseded by xt_mark match revision 1)
 228
 229         - xt_recent: the old ipt_recent proc dir
 230           (superseded by /proc/net/xt_recent)
 231
 232 When:   January 2009 or Linux 2.7.0, whichever comes first
 233 Why:    Superseded by newer revisions or modules
 234 Who:    Jan Engelhardt <jengelh@computergmbh.de>
 235
 236 ---------------------------
 237
 238 What:   b43 support for firmware revision < 410
 239 When:   July 2008
 240 Why:    The support code for the old firmware hurts code readability/maintainability
 241         and slightly hurts runtime performance. Bugfixes for the old firmware
 242         are not provided by Broadcom anymore.
 243 Who:    Michael Buesch <mb@bu3sch.de>
 244
 245 ---------------------------
 246
 247 What:   init_mm export
 248 When:   2.6.26
 249 Why:    Not used in-tree. The current out-of-tree users used it to
 250         work around problems in the CPA code which should be resolved
 251         by now. One usecase was described to provide verification code
 252         of the CPA operation. That's a good idea in general, but such
 253         code / infrastructure should be in the kernel and not in some
 254         out-of-tree driver.
 255 Who:    Thomas Gleixner <tglx@linutronix.de>
 256
 257 ----------------------------
 258
 259 What:   usedac i386 kernel parameter
 260 When:   2.6.27
 261 Why:    replaced by allowdac and no dac combination
 262 Who:    Glauber Costa <gcosta@redhat.com>
 263
 264 ---------------------------
 265
 266 What:   remove HID compat support
 267 When:   2.6.29
 268 Why:    needed only as a temporary solution until distros fix themselves up
 269 Who:    Jiri Slaby <jirislaby@gmail.com>
 270
 271 ---------------------------
 272
 273 What: print_fn_descriptor_symbol()
 274 When: October 2009
 275 Why:  The %pF vsprintf format provides the same functionality in a
 276       simpler way.  print_fn_descriptor_symbol() is deprecated but
 277       still present to give out-of-tree modules time to change.
 278 Who:  Bjorn Helgaas <bjorn.helgaas@hp.com>
 279
 280 ---------------------------
 281
 282 What:   /sys/o2cb symlink
 283 When:   January 2010
 284 Why:    /sys/fs/o2cb is the proper location for this information - /sys/o2cb
 285         exists as a symlink for backwards compatibility for old versions of
 286         ocfs2-tools. 2 years should be sufficient time to phase in new versions
 287         which know to look in /sys/fs/o2cb.
 288 Who:    ocfs2-devel@oss.oracle.com
 289
 290 ---------------------------
 291
 292 What:   SCTP_GET_PEER_ADDRS_NUM_OLD, SCTP_GET_PEER_ADDRS_OLD,
 293         SCTP_GET_LOCAL_ADDRS_NUM_OLD, SCTP_GET_LOCAL_ADDRS_OLD
 294 When:   June 2009
 295 Why:    A newer version of the options have been introduced in 2005 that
 296         removes the limitions of the old API.  The sctp library has been
 297         converted to use these new options at the same time.  Any user
 298         space app that directly uses the old options should convert to using
 299         the new options.
 300 Who:    Vlad Yasevich <vladislav.yasevich@hp.com>
 301
 302 ---------------------------
 303
 304 What:   CONFIG_THERMAL_HWMON
 305 When:   January 2009
 306 Why:    This option was introduced just to allow older lm-sensors userspace
 307         to keep working over the upgrade to 2.6.26. At the scheduled time of
 308         removal fixed lm-sensors (2.x or 3.x) should be readily available.
 309 Who:    Rene Herman <rene.herman@gmail.com>
 310
 311 ---------------------------
 312
 313 What:   Code that is now under CONFIG_WIRELESS_EXT_SYSFS
 314         (in net/core/net-sysfs.c)
 315 When:   After the only user (hal) has seen a release with the patches
 316         for enough time, probably some time in 2010.
 317 Why:    Over 1K .text/.data size reduction, data is available in other
 318         ways (ioctls)
 319 Who:    Johannes Berg <johannes@sipsolutions.net>
 320
 321 ---------------------------
 322
 323 What: CONFIG_NF_CT_ACCT
 324 When: 2.6.29
 325 Why:  Accounting can now be enabled/disabled without kernel recompilation.
 326       Currently used only to set a default value for a feature that is also
 327       controlled by a kernel/module/sysfs/sysctl parameter.
 328 Who:  Krzysztof Piotr Oledzki <ole@ans.pl>
 329
 330 ---------------------------
 331
 332 What: ide-scsi (BLK_DEV_IDESCSI)
 333 When: 2.6.29
 334 Why:  The 2.6 kernel supports direct writing to ide CD drives, which
 335       eliminates the need for ide-scsi. The new method is more
 336       efficient in every way.
 337 Who:  FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
 338
 339 ---------------------------
 340
 341 What:   i2c_attach_client(), i2c_detach_client(), i2c_driver->detach_client()
 342 When:   2.6.29 (ideally) or 2.6.30 (more likely)
 343 Why:    Deprecated by the new (standard) device driver binding model. Use
 344         i2c_driver->probe() and ->remove() instead.
 345 Who:    Jean Delvare <khali@linux-fr.org>