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:   dev->power.power_state
  10 When:   July 2007
  11 Why:    Broken design for runtime control over driver power states, confusing
  12         driver-internal runtime power management with:  mechanisms to support
  13         system-wide sleep state transitions; event codes that distinguish
  14         different phases of swsusp "sleep" transitions; and userspace policy
  15         inputs.  This framework was never widely used, and most attempts to
  16         use it were broken.  Drivers should instead be exposing domain-specific
  17         interfaces either to kernel or to userspace.
  18 Who:    Pavel Machek <pavel@suse.cz>
  19
  20 ---------------------------
  21
  22 What:   Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  23 When:   December 2008
  24 Files:  include/linux/video_decoder.h include/linux/videodev.h
  25 Check:  include/linux/video_decoder.h include/linux/videodev.h
  26 Why:    V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
  27         series. The old API have lots of drawbacks and don't provide enough
  28         means to work with all video and audio standards. The newer API is
  29         already available on the main drivers and should be used instead.
  30         Newer drivers should use v4l_compat_translate_ioctl function to handle
  31         old calls, replacing to newer ones.
  32         Decoder iocts are using internally to allow video drivers to
  33         communicate with video decoders. This should also be improved to allow
  34         V4L2 calls being translated into compatible internal ioctls.
  35         Compatibility ioctls will be provided, for a while, via
  36         v4l1-compat module.
  37 Who:    Mauro Carvalho Chehab <mchehab@infradead.org>
  38
  39 ---------------------------
  40
  41 What:   old tuner-3036 i2c driver
  42 When:   2.6.28
  43 Why:    This driver is for VERY old i2c-over-parallel port teletext receiver
  44         boxes. Rather then spending effort on converting this driver to V4L2,
  45         and since it is extremely unlikely that anyone still uses one of these
  46         devices, it was decided to drop it.
  47 Who:    Hans Verkuil <hverkuil@xs4all.nl>
  48         Mauro Carvalho Chehab <mchehab@infradead.org>
  49
  50  ---------------------------
  51
  52 What:   V4L2 dpc7146 driver
  53 When:   2.6.28
  54 Why:    Old driver for the dpc7146 demonstration board that is no longer
  55         relevant. The last time this was tested on actual hardware was
  56         probably around 2002. Since this is a driver for a demonstration
  57         board the decision was made to remove it rather than spending a
  58         lot of effort continually updating this driver to stay in sync
  59         with the latest internal V4L2 or I2C API.
  60 Who:    Hans Verkuil <hverkuil@xs4all.nl>
  61         Mauro Carvalho Chehab <mchehab@infradead.org>
  62
  63 ---------------------------
  64
  65 What:   PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  66 When:   November 2005
  67 Files:  drivers/pcmcia/: pcmcia_ioctl.c
  68 Why:    With the 16-bit PCMCIA subsystem now behaving (almost) like a
  69         normal hotpluggable bus, and with it using the default kernel
  70         infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  71         control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  72         unnecessary, and makes further cleanups and integration of the
  73         PCMCIA subsystem into the Linux kernel device driver model more
  74         difficult. The features provided by cardmgr and cardctl are either
  75         handled by the kernel itself now or are available in the new
  76         pcmciautils package available at
  77         http://kernel.org/pub/linux/utils/kernel/pcmcia/
  78 Who:    Dominik Brodowski <linux@brodo.de>
  79
  80 ---------------------------
  81
  82 What:   sys_sysctl
  83 When:   September 2010
  84 Option: CONFIG_SYSCTL_SYSCALL
  85 Why:    The same information is available in a more convenient from
  86         /proc/sys, and none of the sysctl variables appear to be
  87         important performance wise.
  88
  89         Binary sysctls are a long standing source of subtle kernel
  90         bugs and security issues.
  91
  92         When I looked several months ago all I could find after
  93         searching several distributions were 5 user space programs and
  94         glibc (which falls back to /proc/sys) using this syscall.
  95
  96         The man page for sysctl(2) documents it as unusable for user
  97         space programs.
  98
  99         sysctl(2) is not generally ABI compatible to a 32bit user
 100         space application on a 64bit and a 32bit kernel.
 101
 102         For the last several months the policy has been no new binary
 103         sysctls and no one has put forward an argument to use them.
 104
 105         Binary sysctls issues seem to keep happening appearing so
 106         properly deprecating them (with a warning to user space) and a
 107         2 year grace warning period will mean eventually we can kill
 108         them and end the pain.
 109
 110         In the mean time individual binary sysctls can be dealt with
 111         in a piecewise fashion.
 112
 113 Who:    Eric Biederman <ebiederm@xmission.com>
 114
 115 ---------------------------
 116
 117 What:   remove EXPORT_SYMBOL(kernel_thread)
 118 When:   August 2006
 119 Files:  arch/*/kernel/*_ksyms.c
 120 Check:  kernel_thread
 121 Why:    kernel_thread is a low-level implementation detail.  Drivers should
 122         use the <linux/kthread.h> API instead which shields them from
 123         implementation details and provides a higherlevel interface that
 124         prevents bugs and code duplication
 125 Who:    Christoph Hellwig <hch@lst.de>
 126
 127 ---------------------------
 128
 129 What:   eepro100 network driver
 130 When:   January 2007
 131 Why:    replaced by the e100 driver
 132 Who:    Adrian Bunk <bunk@stusta.de>
 133
 134 ---------------------------
 135
 136 What:   Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
 137         (temporary transition config option provided until then)
 138         The transition config option will also be removed at the same time.
 139 When:   before 2.6.19
 140 Why:    Unused symbols are both increasing the size of the kernel binary
 141         and are often a sign of "wrong API"
 142 Who:    Arjan van de Ven <arjan@linux.intel.com>
 143
 144 ---------------------------
 145
 146 What:   PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
 147 When:   October 2008
 148 Why:    The stacking of class devices makes these values misleading and
 149         inconsistent.
 150         Class devices should not carry any of these properties, and bus
 151         devices have SUBSYTEM and DRIVER as a replacement.
 152 Who:    Kay Sievers <kay.sievers@suse.de>
 153
 154 ---------------------------
 155
 156 What:   ACPI procfs interface
 157 When:   July 2008
 158 Why:    ACPI sysfs conversion should be finished by January 2008.
 159         ACPI procfs interface will be removed in July 2008 so that
 160         there is enough time for the user space to catch up.
 161 Who:    Zhang Rui <rui.zhang@intel.com>
 162
 163 ---------------------------
 164
 165 What:   /proc/acpi/button
 166 When:   August 2007
 167 Why:    /proc/acpi/button has been replaced by events to the input layer
 168         since 2.6.20.
 169 Who:    Len Brown <len.brown@intel.com>
 170
 171 ---------------------------
 172
 173 What:   /proc/acpi/event
 174 When:   February 2008
 175 Why:    /proc/acpi/event has been replaced by events via the input layer
 176         and netlink since 2.6.23.
 177 Who:    Len Brown <len.brown@intel.com>
 178
 179 ---------------------------
 180
 181 What: libata spindown skipping and warning
 182 When: Dec 2008
 183 Why:  Some halt(8) implementations synchronize caches for and spin
 184       down libata disks because libata didn't use to spin down disk on
 185       system halt (only synchronized caches).
 186       Spin down on system halt is now implemented.  sysfs node
 187       /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
 188       spin down support is available.
 189       Because issuing spin down command to an already spun down disk
 190       makes some disks spin up just to spin down again, libata tracks
 191       device spindown status to skip the extra spindown command and
 192       warn about it.
 193       This is to give userspace tools the time to get updated and will
 194       be removed after userspace is reasonably updated.
 195 Who:  Tejun Heo <htejun@gmail.com>
 196
 197 ---------------------------
 198
 199 What:   i386/x86_64 bzImage symlinks
 200 When:   April 2010
 201
 202 Why:    The i386/x86_64 merge provides a symlink to the old bzImage
 203         location so not yet updated user space tools, e.g. package
 204         scripts, do not break.
 205 Who:    Thomas Gleixner <tglx@linutronix.de>
 206
 207 ---------------------------
 208
 209 What (Why):
 210         - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
 211           (superseded by xt_TOS/xt_tos target & match)
 212
 213         - "forwarding" header files like ipt_mac.h in
 214           include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/
 215
 216         - xt_CONNMARK match revision 0
 217           (superseded by xt_CONNMARK match revision 1)
 218
 219         - xt_MARK target revisions 0 and 1
 220           (superseded by xt_MARK match revision 2)
 221
 222         - xt_connmark match revision 0
 223           (superseded by xt_connmark match revision 1)
 224
 225         - xt_conntrack match revision 0
 226           (superseded by xt_conntrack match revision 1)
 227
 228         - xt_iprange match revision 0,
 229           include/linux/netfilter_ipv4/ipt_iprange.h
 230           (superseded by xt_iprange match revision 1)
 231
 232         - xt_mark match revision 0
 233           (superseded by xt_mark match revision 1)
 234
 235 When:   January 2009 or Linux 2.7.0, whichever comes first
 236 Why:    Superseded by newer revisions or modules
 237 Who:    Jan Engelhardt <jengelh@computergmbh.de>
 238
 239 ---------------------------
 240
 241 What:   b43 support for firmware revision < 410
 242 When:   July 2008
 243 Why:    The support code for the old firmware hurts code readability/maintainability
 244         and slightly hurts runtime performance. Bugfixes for the old firmware
 245         are not provided by Broadcom anymore.
 246 Who:    Michael Buesch <mb@bu3sch.de>
 247
 248 ---------------------------
 249
 250 What:   init_mm export
 251 When:   2.6.26
 252 Why:    Not used in-tree. The current out-of-tree users used it to
 253         work around problems in the CPA code which should be resolved
 254         by now. One usecase was described to provide verification code
 255         of the CPA operation. That's a good idea in general, but such
 256         code / infrastructure should be in the kernel and not in some
 257         out-of-tree driver.
 258 Who:    Thomas Gleixner <tglx@linutronix.de>
 259
 260 ----------------------------
 261
 262 What:   usedac i386 kernel parameter
 263 When:   2.6.27
 264 Why:    replaced by allowdac and no dac combination
 265 Who:    Glauber Costa <gcosta@redhat.com>
 266
 267 ---------------------------
 268
 269 What:   old style serial driver for ColdFire (CONFIG_SERIAL_COLDFIRE)
 270 When:   2.6.28
 271 Why:    This driver still uses the old interface and has been replaced
 272         by CONFIG_SERIAL_MCF.
 273 Who:    Sebastian Siewior <sebastian@breakpoint.cc>
 274
 275 ---------------------------
 276
 277 What:   /sys/o2cb symlink
 278 When:   January 2010
 279 Why:    /sys/fs/o2cb is the proper location for this information - /sys/o2cb
 280         exists as a symlink for backwards compatibility for old versions of
 281         ocfs2-tools. 2 years should be sufficient time to phase in new versions
 282         which know to look in /sys/fs/o2cb.
 283 Who:    ocfs2-devel@oss.oracle.com
 284
 285 ---------------------------
 286
 287 What:   SCTP_GET_PEER_ADDRS_NUM_OLD, SCTP_GET_PEER_ADDRS_OLD,
 288         SCTP_GET_LOCAL_ADDRS_NUM_OLD, SCTP_GET_LOCAL_ADDRS_OLD
 289 When:   June 2009
 290 Why:    A newer version of the options have been introduced in 2005 that
 291         removes the limitions of the old API.  The sctp library has been
 292         converted to use these new options at the same time.  Any user
 293         space app that directly uses the old options should convert to using
 294         the new options.
 295 Who:    Vlad Yasevich <vladislav.yasevich@hp.com>
 296
 297 ---------------------------
 298
 299 What:   CONFIG_THERMAL_HWMON
 300 When:   January 2009
 301 Why:    This option was introduced just to allow older lm-sensors userspace
 302         to keep working over the upgrade to 2.6.26. At the scheduled time of
 303         removal fixed lm-sensors (2.x or 3.x) should be readily available.
 304 Who:    Rene Herman <rene.herman@gmail.com>
 305
 306 ---------------------------
 307
 308 What:   Code that is now under CONFIG_WIRELESS_EXT_SYSFS
 309         (in net/core/net-sysfs.c)
 310 When:   After the only user (hal) has seen a release with the patches
 311         for enough time, probably some time in 2010.
 312 Why:    Over 1K .text/.data size reduction, data is available in other
 313         ways (ioctls)
 314 Who:    Johannes Berg <johannes@sipsolutions.net>
 315
 316 ---------------------------
 317
 318 What: CONFIG_NF_CT_ACCT
 319 When: 2.6.29
 320 Why:  Accounting can now be enabled/disabled without kernel recompilation.
 321       Currently used only to set a default value for a feature that is also
 322       controlled by a kernel/module/sysfs/sysctl parameter.
 323 Who:  Krzysztof Piotr Oledzki <ole@ans.pl>
 324
 325 ---------------------------
 326
 327 What: ide-scsi (BLK_DEV_IDESCSI)
 328 When: 2.6.29
 329 Why:  The 2.6 kernel supports direct writing to ide CD drives, which
 330       eliminates the need for ide-scsi. The new method is more
 331       efficient in every way.
 332 Who:  FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>