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:   ide-tape driver
 176 When:   July 2008
 177 Files:  drivers/ide/ide-tape.c
 178 Why:    This driver might not have any users anymore and maintaining it for no
 179         reason is an effort no one wants to make.
 180 Who:    Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>, Borislav Petkov
 181         <petkovbb@googlemail.com>
 182
 183 ---------------------------
 184
 185 What: libata spindown skipping and warning
 186 When: Dec 2008
 187 Why:  Some halt(8) implementations synchronize caches for and spin
 188       down libata disks because libata didn't use to spin down disk on
 189       system halt (only synchronized caches).
 190       Spin down on system halt is now implemented.  sysfs node
 191       /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
 192       spin down support is available.
 193       Because issuing spin down command to an already spun down disk
 194       makes some disks spin up just to spin down again, libata tracks
 195       device spindown status to skip the extra spindown command and
 196       warn about it.
 197       This is to give userspace tools the time to get updated and will
 198       be removed after userspace is reasonably updated.
 199 Who:  Tejun Heo <htejun@gmail.com>
 200
 201 ---------------------------
 202
 203 What: The arch/ppc and include/asm-ppc directories
 204 When: Jun 2008
 205 Why:  The arch/powerpc tree is the merged architecture for ppc32 and ppc64
 206       platforms.  Currently there are efforts underway to port the remaining
 207       arch/ppc platforms to the merged tree.  New submissions to the arch/ppc
 208       tree have been frozen with the 2.6.22 kernel release and that tree will
 209       remain in bug-fix only mode until its scheduled removal.  Platforms
 210       that are not ported by June 2008 will be removed due to the lack of an
 211       interested maintainer.
 212 Who:  linuxppc-dev@ozlabs.org
 213
 214 ---------------------------
 215
 216 What:   sk98lin network driver
 217 When:   Feburary 2008
 218 Why:    In kernel tree version of driver is unmaintained. Sk98lin driver
 219         replaced by the skge driver.
 220 Who:    Stephen Hemminger <shemminger@linux-foundation.org>
 221
 222 ---------------------------
 223
 224 What:   i386/x86_64 bzImage symlinks
 225 When:   April 2008
 226
 227 Why:    The i386/x86_64 merge provides a symlink to the old bzImage
 228         location so not yet updated user space tools, e.g. package
 229         scripts, do not break.
 230 Who:    Thomas Gleixner <tglx@linutronix.de>
 231
 232 ---------------------------
 233
 234 ---------------------------
 235
 236 What:   i2c-i810, i2c-prosavage and i2c-savage4
 237 When:   May 2008
 238 Why:    These drivers are superseded by i810fb, intelfb and savagefb.
 239 Who:    Jean Delvare <khali@linux-fr.org>
 240
 241 ---------------------------
 242
 243 What:   bcm43xx wireless network driver
 244 When:   2.6.26
 245 Files:  drivers/net/wireless/bcm43xx
 246 Why:    This driver's functionality has been replaced by the
 247         mac80211-based b43 and b43legacy drivers.
 248 Who:    John W. Linville <linville@tuxdriver.com>
 249
 250 ---------------------------
 251
 252 What:   ieee80211 softmac wireless networking component
 253 When:   2.6.26 (or after removal of bcm43xx and port of zd1211rw to mac80211)
 254 Files:  net/ieee80211/softmac
 255 Why:    No in-kernel drivers will depend on it any longer.
 256 Who:    John W. Linville <linville@tuxdriver.com>
 257
 258 ---------------------------
 259
 260 What:   rc80211-simple rate control algorithm for mac80211
 261 When:   2.6.26
 262 Files:  net/mac80211/rc80211-simple.c
 263 Why:    This algorithm was provided for reference but always exhibited bad
 264         responsiveness and performance and has some serious flaws. It has been
 265         replaced by rc80211-pid.
 266 Who:    Stefano Brivio <stefano.brivio@polimi.it>
 267
 268 ---------------------------
 269
 270 What (Why):
 271         - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
 272           (superseded by xt_TOS/xt_tos target & match)
 273
 274         - "forwarding" header files like ipt_mac.h in
 275           include/linux/netfilter_ipv4/ and include/linux/netfilter_ipv6/
 276
 277         - xt_CONNMARK match revision 0
 278           (superseded by xt_CONNMARK match revision 1)
 279
 280         - xt_MARK target revisions 0 and 1
 281           (superseded by xt_MARK match revision 2)
 282
 283         - xt_connmark match revision 0
 284           (superseded by xt_connmark match revision 1)
 285
 286         - xt_conntrack match revision 0
 287           (superseded by xt_conntrack match revision 1)
 288
 289         - xt_iprange match revision 0,
 290           include/linux/netfilter_ipv4/ipt_iprange.h
 291           (superseded by xt_iprange match revision 1)
 292
 293         - xt_mark match revision 0
 294           (superseded by xt_mark match revision 1)
 295
 296 When:   January 2009 or Linux 2.7.0, whichever comes first
 297 Why:    Superseded by newer revisions or modules
 298 Who:    Jan Engelhardt <jengelh@computergmbh.de>
 299
 300 ---------------------------
 301
 302 What:   b43 support for firmware revision < 410
 303 When:   July 2008
 304 Why:    The support code for the old firmware hurts code readability/maintainability
 305         and slightly hurts runtime performance. Bugfixes for the old firmware
 306         are not provided by Broadcom anymore.
 307 Who:    Michael Buesch <mb@bu3sch.de>
 308
 309 ---------------------------
 310
 311 What:   Solaris/SunOS syscall and binary support on Sparc
 312 When:   2.6.26
 313 Why:    Largely unmaintained and almost entirely unused.  File system
 314         layering used to divert library and dynamic linker searches to
 315         /usr/gnemul is extremely buggy and unfixable.  Making it work
 316         is largely pointless as without a lot of work only the most
 317         trivial of Solaris binaries can work with the emulation code.
 318 Who:    David S. Miller <davem@davemloft.net>
 319
 320 ---------------------------
 321
 322 What:   init_mm export
 323 When:   2.6.26
 324 Why:    Not used in-tree. The current out-of-tree users used it to
 325         work around problems in the CPA code which should be resolved
 326         by now. One usecase was described to provide verification code
 327         of the CPA operation. That's a good idea in general, but such
 328         code / infrastructure should be in the kernel and not in some
 329         out-of-tree driver.
 330 Who:    Thomas Gleixner <tglx@linutronix.de>