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:   old NCR53C9x driver
  23 When:   October 2007
  24 Why:    Replaced by the much better esp_scsi driver.  Actual low-level
  25         driver can be ported over almost trivially.
  26 Who:    David Miller <davem@davemloft.net>
  27         Christoph Hellwig <hch@lst.de>
  28
  29 ---------------------------
  30
  31 What:   Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  32 When:   December 2008
  33 Files:  include/linux/video_decoder.h include/linux/videodev.h
  34 Check:  include/linux/video_decoder.h include/linux/videodev.h
  35 Why:    V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
  36         series. The old API have lots of drawbacks and don't provide enough
  37         means to work with all video and audio standards. The newer API is
  38         already available on the main drivers and should be used instead.
  39         Newer drivers should use v4l_compat_translate_ioctl function to handle
  40         old calls, replacing to newer ones.
  41         Decoder iocts are using internally to allow video drivers to
  42         communicate with video decoders. This should also be improved to allow
  43         V4L2 calls being translated into compatible internal ioctls.
  44         Compatibility ioctls will be provided, for a while, via
  45         v4l1-compat module.
  46 Who:    Mauro Carvalho Chehab <mchehab@infradead.org>
  47
  48 ---------------------------
  49
  50 What:   PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  51 When:   November 2005
  52 Files:  drivers/pcmcia/: pcmcia_ioctl.c
  53 Why:    With the 16-bit PCMCIA subsystem now behaving (almost) like a
  54         normal hotpluggable bus, and with it using the default kernel
  55         infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  56         control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  57         unnecessary, and makes further cleanups and integration of the
  58         PCMCIA subsystem into the Linux kernel device driver model more
  59         difficult. The features provided by cardmgr and cardctl are either
  60         handled by the kernel itself now or are available in the new
  61         pcmciautils package available at
  62         http://kernel.org/pub/linux/utils/kernel/pcmcia/
  63 Who:    Dominik Brodowski <linux@brodo.de>
  64
  65 ---------------------------
  66
  67 What:   sys_sysctl
  68 When:   September 2010
  69 Option: CONFIG_SYSCTL_SYSCALL
  70 Why:    The same information is available in a more convenient from
  71         /proc/sys, and none of the sysctl variables appear to be
  72         important performance wise.
  73
  74         Binary sysctls are a long standing source of subtle kernel
  75         bugs and security issues.
  76
  77         When I looked several months ago all I could find after
  78         searching several distributions were 5 user space programs and
  79         glibc (which falls back to /proc/sys) using this syscall.
  80
  81         The man page for sysctl(2) documents it as unusable for user
  82         space programs.
  83
  84         sysctl(2) is not generally ABI compatible to a 32bit user
  85         space application on a 64bit and a 32bit kernel.
  86
  87         For the last several months the policy has been no new binary
  88         sysctls and no one has put forward an argument to use them.
  89
  90         Binary sysctls issues seem to keep happening appearing so
  91         properly deprecating them (with a warning to user space) and a
  92         2 year grace warning period will mean eventually we can kill
  93         them and end the pain.
  94
  95         In the mean time individual binary sysctls can be dealt with
  96         in a piecewise fashion.
  97
  98 Who:    Eric Biederman <ebiederm@xmission.com>
  99
 100 ---------------------------
 101
 102 What:   remove EXPORT_SYMBOL(kernel_thread)
 103 When:   August 2006
 104 Files:  arch/*/kernel/*_ksyms.c
 105 Check:  kernel_thread
 106 Why:    kernel_thread is a low-level implementation detail.  Drivers should
 107         use the <linux/kthread.h> API instead which shields them from
 108         implementation details and provides a higherlevel interface that
 109         prevents bugs and code duplication
 110 Who:    Christoph Hellwig <hch@lst.de>
 111
 112 ---------------------------
 113
 114 What:   eepro100 network driver
 115 When:   January 2007
 116 Why:    replaced by the e100 driver
 117 Who:    Adrian Bunk <bunk@stusta.de>
 118
 119 ---------------------------
 120
 121 What:   Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
 122         (temporary transition config option provided until then)
 123         The transition config option will also be removed at the same time.
 124 When:   before 2.6.19
 125 Why:    Unused symbols are both increasing the size of the kernel binary
 126         and are often a sign of "wrong API"
 127 Who:    Arjan van de Ven <arjan@linux.intel.com>
 128
 129 ---------------------------
 130
 131 What:   vm_ops.nopage
 132 When:   Soon, provided in-kernel callers have been converted
 133 Why:    This interface is replaced by vm_ops.fault, but it has been around
 134         forever, is used by a lot of drivers, and doesn't cost much to
 135         maintain.
 136 Who:    Nick Piggin <npiggin@suse.de>
 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: The arch/ppc and include/asm-ppc directories
 194 When: Jun 2008
 195 Why:  The arch/powerpc tree is the merged architecture for ppc32 and ppc64
 196       platforms.  Currently there are efforts underway to port the remaining
 197       arch/ppc platforms to the merged tree.  New submissions to the arch/ppc
 198       tree have been frozen with the 2.6.22 kernel release and that tree will
 199       remain in bug-fix only mode until its scheduled removal.  Platforms
 200       that are not ported by June 2008 will be removed due to the lack of an
 201       interested maintainer.
 202 Who:  linuxppc-dev@ozlabs.org
 203
 204 ---------------------------
 205
 206 What:   i386/x86_64 bzImage symlinks
 207 When:   April 2010
 208
 209 Why:    The i386/x86_64 merge provides a symlink to the old bzImage
 210         location so not yet updated user space tools, e.g. package
 211         scripts, do not break.
 212 Who:    Thomas Gleixner <tglx@linutronix.de>
 213
 214 ---------------------------
 215
 216 What:   i2c-i810, i2c-prosavage and i2c-savage4
 217 When:   May 2008
 218 Why:    These drivers are superseded by i810fb, intelfb and savagefb.
 219 Who:    Jean Delvare <khali@linux-fr.org>
 220
 221 ---------------------------
 222
 223 What (Why):
 224         - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
 225           (superseded by xt_TOS/xt_tos target & match)
 226
 227         - "forwarding" header files like ipt_mac.h in
 228           include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/
 229
 230         - xt_CONNMARK match revision 0
 231           (superseded by xt_CONNMARK match revision 1)
 232
 233         - xt_MARK target revisions 0 and 1
 234           (superseded by xt_MARK match revision 2)
 235
 236         - xt_connmark match revision 0
 237           (superseded by xt_connmark match revision 1)
 238
 239         - xt_conntrack match revision 0
 240           (superseded by xt_conntrack match revision 1)
 241
 242         - xt_iprange match revision 0,
 243           include/linux/netfilter_ipv4/ipt_iprange.h
 244           (superseded by xt_iprange match revision 1)
 245
 246         - xt_mark match revision 0
 247           (superseded by xt_mark match revision 1)
 248
 249 When:   January 2009 or Linux 2.7.0, whichever comes first
 250 Why:    Superseded by newer revisions or modules
 251 Who:    Jan Engelhardt <jengelh@computergmbh.de>
 252
 253 ---------------------------
 254
 255 What:   b43 support for firmware revision < 410
 256 When:   July 2008
 257 Why:    The support code for the old firmware hurts code readability/maintainability
 258         and slightly hurts runtime performance. Bugfixes for the old firmware
 259         are not provided by Broadcom anymore.
 260 Who:    Michael Buesch <mb@bu3sch.de>
 261
 262 ---------------------------
 263
 264 What:   init_mm export
 265 When:   2.6.26
 266 Why:    Not used in-tree. The current out-of-tree users used it to
 267         work around problems in the CPA code which should be resolved
 268         by now. One usecase was described to provide verification code
 269         of the CPA operation. That's a good idea in general, but such
 270         code / infrastructure should be in the kernel and not in some
 271         out-of-tree driver.
 272 Who:    Thomas Gleixner <tglx@linutronix.de>
 273
 274 ----------------------------
 275
 276 What:   usedac i386 kernel parameter
 277 When:   2.6.27
 278 Why:    replaced by allowdac and no dac combination
 279 Who:    Glauber Costa <gcosta@redhat.com>
 280
 281 ---------------------------
 282
 283 What:   /sys/o2cb symlink
 284 When:   January 2010
 285 Why:    /sys/fs/o2cb is the proper location for this information - /sys/o2cb
 286         exists as a symlink for backwards compatibility for old versions of
 287         ocfs2-tools. 2 years should be sufficient time to phase in new versions
 288         which know to look in /sys/fs/o2cb.
 289 Who:    ocfs2-devel@oss.oracle.com
 290
 291 ---------------------------
 292
 293 What:   asm/semaphore.h
 294 When:   2.6.26
 295 Why:    Implementation became generic; users should now include
 296         linux/semaphore.h instead.
 297 Who:    Matthew Wilcox <willy@linux.intel.com>