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:   /sys/devices/.../power/state
  10         dev->power.power_state
  11         dpm_runtime_{suspend,resume)()
  12 When:   July 2007
  13 Why:    Broken design for runtime control over driver power states, confusing
  14         driver-internal runtime power management with:  mechanisms to support
  15         system-wide sleep state transitions; event codes that distinguish
  16         different phases of swsusp "sleep" transitions; and userspace policy
  17         inputs.  This framework was never widely used, and most attempts to
  18         use it were broken.  Drivers should instead be exposing domain-specific
  19         interfaces either to kernel or to userspace.
  20 Who:    Pavel Machek <pavel@suse.cz>
  21
  22 ---------------------------
  23
  24 What:   RAW driver (CONFIG_RAW_DRIVER)
  25 When:   December 2005
  26 Why:    declared obsolete since kernel 2.6.3
  27         O_DIRECT can be used instead
  28 Who:    Adrian Bunk <bunk@stusta.de>
  29
  30 ---------------------------
  31
  32 What:   raw1394: requests of type RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN
  33 When:   June 2007
  34 Why:    Deprecated in favour of the more efficient and robust rawiso interface.
  35         Affected are applications which use the deprecated part of libraw1394
  36         (raw1394_iso_write, raw1394_start_iso_write, raw1394_start_iso_rcv,
  37         raw1394_stop_iso_rcv) or bypass libraw1394.
  38 Who:    Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
  39
  40 ---------------------------
  41
  42 What:   dv1394 driver (CONFIG_IEEE1394_DV1394)
  43 When:   June 2007
  44 Why:    Replaced by raw1394 + userspace libraries, notably libiec61883.  This
  45         shift of application support has been indicated on www.linux1394.org
  46         and developers' mailinglists for quite some time.  Major applications
  47         have been converted, with the exception of ffmpeg and hence xine.
  48         Piped output of dvgrab2 is a partial equivalent to dv1394.
  49 Who:    Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
  50
  51 ---------------------------
  52
  53 What:   ieee1394 core's unused exports (CONFIG_IEEE1394_EXPORT_FULL_API)
  54 When:   January 2007
  55 Why:    There are no projects known to use these exported symbols, except
  56         dfg1394 (uses one symbol whose functionality is core-internal now).
  57 Who:    Stefan Richter <stefanr@s5r6.in-berlin.de>
  58
  59 ---------------------------
  60
  61 What:   ieee1394's *_oui sysfs attributes (CONFIG_IEEE1394_OUI_DB)
  62 When:   January 2007
  63 Files:  drivers/ieee1394/: oui.db, oui2c.sh
  64 Why:    big size, little value
  65 Who:    Stefan Richter <stefanr@s5r6.in-berlin.de>
  66
  67 ---------------------------
  68
  69 What:   Video4Linux API 1 ioctls and video_decoder.h from Video devices.
  70 When:   December 2006
  71 Why:    V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
  72         series. The old API have lots of drawbacks and don't provide enough
  73         means to work with all video and audio standards. The newer API is
  74         already available on the main drivers and should be used instead.
  75         Newer drivers should use v4l_compat_translate_ioctl function to handle
  76         old calls, replacing to newer ones.
  77         Decoder iocts are using internally to allow video drivers to
  78         communicate with video decoders. This should also be improved to allow
  79         V4L2 calls being translated into compatible internal ioctls.
  80 Who:    Mauro Carvalho Chehab <mchehab@brturbo.com.br>
  81
  82 ---------------------------
  83
  84 What:   PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl])
  85 When:   November 2005
  86 Files:  drivers/pcmcia/: pcmcia_ioctl.c
  87 Why:    With the 16-bit PCMCIA subsystem now behaving (almost) like a
  88         normal hotpluggable bus, and with it using the default kernel
  89         infrastructure (hotplug, driver core, sysfs) keeping the PCMCIA
  90         control ioctl needed by cardmgr and cardctl from pcmcia-cs is
  91         unnecessary, and makes further cleanups and integration of the
  92         PCMCIA subsystem into the Linux kernel device driver model more
  93         difficult. The features provided by cardmgr and cardctl are either
  94         handled by the kernel itself now or are available in the new
  95         pcmciautils package available at
  96         http://kernel.org/pub/linux/utils/kernel/pcmcia/
  97 Who:    Dominik Brodowski <linux@brodo.de>
  98
  99 ---------------------------
 100
 101 What:   remove EXPORT_SYMBOL(kernel_thread)
 102 When:   August 2006
 103 Files:  arch/*/kernel/*_ksyms.c
 104 Why:    kernel_thread is a low-level implementation detail.  Drivers should
 105         use the <linux/kthread.h> API instead which shields them from
 106         implementation details and provides a higherlevel interface that
 107         prevents bugs and code duplication
 108 Who:    Christoph Hellwig <hch@lst.de>
 109
 110 ---------------------------
 111
 112 What:   CONFIG_FORCED_INLINING
 113 When:   June 2006
 114 Why:    Config option is there to see if gcc is good enough. (in january
 115         2006). If it is, the behavior should just be the default. If it's not,
 116         the option should just go away entirely.
 117 Who:    Arjan van de Ven
 118
 119 ---------------------------
 120
 121 What:   eepro100 network driver
 122 When:   January 2007
 123 Why:    replaced by the e100 driver
 124 Who:    Adrian Bunk <bunk@stusta.de>
 125
 126 ---------------------------
 127
 128 What:  drivers depending on OSS_OBSOLETE_DRIVER
 129 When:  options in 2.6.20, code in 2.6.22
 130 Why:   OSS drivers with ALSA replacements
 131 Who:   Adrian Bunk <bunk@stusta.de>
 132
 133 ---------------------------
 134
 135 What:   pci_module_init(driver)
 136 When:   January 2007
 137 Why:    Is replaced by pci_register_driver(pci_driver).
 138 Who:    Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@suse.de>
 139
 140 ---------------------------
 141
 142 What:   Usage of invalid timevals in setitimer
 143 When:   March 2007
 144 Why:    POSIX requires to validate timevals in the setitimer call. This
 145         was never done by Linux. The invalid (e.g. negative timevals) were
 146         silently converted to more or less random timeouts and intervals.
 147         Until the removal a per boot limited number of warnings is printed
 148         and the timevals are sanitized.
 149
 150 Who:    Thomas Gleixner <tglx@linutronix.de>
 151
 152 ---------------------------
 153
 154 What:   Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
 155         (temporary transition config option provided until then)
 156         The transition config option will also be removed at the same time.
 157 When:   before 2.6.19
 158 Why:    Unused symbols are both increasing the size of the kernel binary
 159         and are often a sign of "wrong API"
 160 Who:    Arjan van de Ven <arjan@linux.intel.com>
 161
 162 ---------------------------
 163
 164 What:   mount/umount uevents
 165 When:   February 2007
 166 Why:    These events are not correct, and do not properly let userspace know
 167         when a file system has been mounted or unmounted.  Userspace should
 168         poll the /proc/mounts file instead to detect this properly.
 169 Who:    Greg Kroah-Hartman <gregkh@suse.de>
 170
 171 ---------------------------
 172
 173 What:   USB driver API moves to EXPORT_SYMBOL_GPL
 174 When:   February 2008
 175 Files:  include/linux/usb.h, drivers/usb/core/driver.c
 176 Why:    The USB subsystem has changed a lot over time, and it has been
 177         possible to create userspace USB drivers using usbfs/libusb/gadgetfs
 178         that operate as fast as the USB bus allows.  Because of this, the USB
 179         subsystem will not be allowing closed source kernel drivers to
 180         register with it, after this grace period is over.  If anyone needs
 181         any help in converting their closed source drivers over to use the
 182         userspace filesystems, please contact the
 183         linux-usb-devel@lists.sourceforge.net mailing list, and the developers
 184         there will be glad to help you out.
 185 Who:    Greg Kroah-Hartman <gregkh@suse.de>
 186
 187 ---------------------------
 188
 189 What:   find_trylock_page
 190 When:   January 2007
 191 Why:    The interface no longer has any callers left in the kernel. It
 192         is an odd interface (compared with other find_*_page functions), in
 193         that it does not take a refcount to the page, only the page lock.
 194         It should be replaced with find_get_page or find_lock_page if possible.
 195         This feature removal can be reevaluated if users of the interface
 196         cannot cleanly use something else.
 197 Who:    Nick Piggin <npiggin@suse.de>
 198
 199 ---------------------------
 200
 201 What:   Interrupt only SA_* flags
 202 When:   Januar 2007
 203 Why:    The interrupt related SA_* flags are replaced by IRQF_* to move them
 204         out of the signal namespace.
 205
 206 Who:    Thomas Gleixner <tglx@linutronix.de>
 207
 208 ---------------------------
 209
 210 What:   PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
 211 When:   October 2008
 212 Why:    The stacking of class devices makes these values misleading and
 213         inconsistent.
 214         Class devices should not carry any of these properties, and bus
 215         devices have SUBSYTEM and DRIVER as a replacement.
 216 Who:    Kay Sievers <kay.sievers@suse.de>
 217
 218 ---------------------------
 219
 220 What:   i2c-isa
 221 When:   December 2006
 222 Why:    i2c-isa is a non-sense and doesn't fit in the device driver
 223         model. Drivers relying on it are better implemented as platform
 224         drivers.
 225 Who:    Jean Delvare <khali@linux-fr.org>
 226
 227 ---------------------------
 228
 229 What:   i2c_adapter.dev
 230         i2c_adapter.list
 231 When:   July 2007
 232 Why:    Superfluous, given i2c_adapter.class_dev:
 233           * The "dev" was a stand-in for the physical device node that legacy
 234             drivers would not have; but now it's almost always present.  Any
 235             remaining legacy drivers must upgrade (they now trigger warnings).
 236           * The "list" duplicates class device children.
 237         The delay in removing this is so upgraded lm_sensors and libsensors
 238         can get deployed.  (Removal causes minor changes in the sysfs layout,
 239         notably the location of the adapter type name and parenting the i2c
 240         client hardware directly from their controller.)
 241 Who:    Jean Delvare <khali@linux-fr.org>,
 242         David Brownell <dbrownell@users.sourceforge.net>
 243
 244 ---------------------------
 245
 246 What:   IPv4 only connection tracking/NAT/helpers
 247 When:   2.6.22
 248 Why:    The new layer 3 independant connection tracking replaces the old
 249         IPv4 only version. After some stabilization of the new code the
 250         old one will be removed.
 251 Who:    Patrick McHardy <kaber@trash.net>
 252
 253 ---------------------------
 254
 255 What:   ACPI hooks (X86_SPEEDSTEP_CENTRINO_ACPI) in speedstep-centrino driver
 256 When:   December 2006
 257 Why:    Speedstep-centrino driver with ACPI hooks and acpi-cpufreq driver are
 258         functionally very much similar. They talk to ACPI in same way. Only
 259         difference between them is the way they do frequency transitions.
 260         One uses MSRs and the other one uses IO ports. Functionaliy of
 261         speedstep_centrino with ACPI hooks is now merged into acpi-cpufreq.
 262         That means one common driver will support all Intel Enhanced Speedstep
 263         capable CPUs. That means less confusion over name of
 264         speedstep-centrino driver (with that driver supposed to be used on
 265         non-centrino platforms). That means less duplication of code and
 266         less maintenance effort and no possibility of these two drivers
 267         going out of sync.
 268         Current users of speedstep_centrino with ACPI hooks are requested to
 269         switch over to acpi-cpufreq driver. speedstep-centrino will continue
 270         to work using older non-ACPI static table based scheme even after this
 271         date.
 272
 273 Who:    Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 274
 275 ---------------------------
 276
 277 What:   ACPI hotkey driver (CONFIG_ACPI_HOTKEY)
 278 When:   2.6.21
 279 Why:    hotkey.c was an attempt to consolidate multiple drivers that use
 280         ACPI to implement hotkeys.  However, hotkeys are not documented
 281         in the ACPI specification, so the drivers used undocumented
 282         vendor-specific hooks and turned out to be more different than
 283         the same.
 284
 285         Further, the keys and the features supplied by each platform
 286         are different, so there will always be a need for
 287         platform-specific drivers.
 288
 289         So the new plan is to delete hotkey.c and instead, work on the
 290         platform specific drivers to try to make them look the same
 291         to the user when they supply the same features.
 292
 293         hotkey.c has always depended on CONFIG_EXPERIMENTAL
 294
 295 Who:    Len Brown <len.brown@intel.com>
 296
 297 ---------------------------
 298
 299 What:   /sys/firmware/acpi/namespace
 300 When:   2.6.21
 301 Why:    The ACPI namespace is effectively the symbol list for
 302         the BIOS.  The device names are completely arbitrary
 303         and have no place being exposed to user-space.
 304
 305         For those interested in the BIOS ACPI namespace,
 306         the BIOS can be extracted and disassembled with acpidump
 307         and iasl as documented in the pmtools package here:
 308         http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/utils
 309
 310 Who:    Len Brown <len.brown@intel.com>
 311
 312 ---------------------------
 313
 314 What:   /proc/acpi/button
 315 When:   August 2007
 316 Why:    /proc/acpi/button has been replaced by events to the input layer
 317         since 2.6.20.
 318 Who:    Len Brown <len.brown@intel.com>
 319
 320 ---------------------------