1The following is a list of files and features that are going to be 2removed in the kernel source tree. Every entry should contain what 3exactly is going away, why it is happening, and who is going to be doing 4the work. When the feature is removed from the kernel, it should also 5be removed from this file. 6 7--------------------------- 8 9What: x86 floppy disable_hlt 10When: 2012 11Why: ancient workaround of dubious utility clutters the 12 code used by everybody else. 13Who: Len Brown <len.brown@intel.com> 14 15--------------------------- 16 17What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle 18When: 2012 19Why: This optional sub-feature of APM is of dubious reliability, 20 and ancient APM laptops are likely better served by calling HLT. 21 Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting 22 the pm_idle function pointer to modules. 23Who: Len Brown <len.brown@intel.com> 24 25---------------------------- 26 27What: x86_32 "no-hlt" cmdline param 28When: 2012 29Why: remove a branch from idle path, simplify code used by everybody. 30 This option disabled the use of HLT in idle and machine_halt() 31 for hardware that was flakey 15-years ago. Today we have 32 "idle=poll" that removed HLT from idle, and so if such a machine 33 is still running the upstream kernel, "idle=poll" is likely sufficient. 34Who: Len Brown <len.brown@intel.com> 35 36---------------------------- 37 38What: x86 "idle=mwait" cmdline param 39When: 2012 40Why: simplify x86 idle code 41Who: Len Brown <len.brown@intel.com> 42 43---------------------------- 44 45What: PRISM54 46When: 2.6.34 47 48Why: prism54 FullMAC PCI / Cardbus devices used to be supported only by the 49 prism54 wireless driver. After Intersil stopped selling these 50 devices in preference for the newer more flexible SoftMAC devices 51 a SoftMAC device driver was required and prism54 did not support 52 them. The p54pci driver now exists and has been present in the kernel for 53 a while. This driver supports both SoftMAC devices and FullMAC devices. 54 The main difference between these devices was the amount of memory which 55 could be used for the firmware. The SoftMAC devices support a smaller 56 amount of memory. Because of this the SoftMAC firmware fits into FullMAC 57 devices's memory. p54pci supports not only PCI / Cardbus but also USB 58 and SPI. Since p54pci supports all devices prism54 supports 59 you will have a conflict. I'm not quite sure how distributions are 60 handling this conflict right now. prism54 was kept around due to 61 claims users may experience issues when using the SoftMAC driver. 62 Time has passed users have not reported issues. If you use prism54 63 and for whatever reason you cannot use p54pci please let us know! 64 E-mail us at: linux-wireless@vger.kernel.org 65 66 For more information see the p54 wiki page: 67 68 http://wireless.kernel.org/en/users/Drivers/p54 69 70Who: Luis R. Rodriguez <lrodriguez@atheros.com> 71 72--------------------------- 73 74What: IRQF_SAMPLE_RANDOM 75Check: IRQF_SAMPLE_RANDOM 76When: July 2009 77 78Why: Many of IRQF_SAMPLE_RANDOM users are technically bogus as entropy 79 sources in the kernel's current entropy model. To resolve this, every 80 input point to the kernel's entropy pool needs to better document the 81 type of entropy source it actually is. This will be replaced with 82 additional add_*_randomness functions in drivers/char/random.c 83 84Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com> 85 86--------------------------- 87 88What: Deprecated snapshot ioctls 89When: 2.6.36 90 91Why: The ioctls in kernel/power/user.c were marked as deprecated long time 92 ago. Now they notify users about that so that they need to replace 93 their userspace. After some more time, remove them completely. 94 95Who: Jiri Slaby <jirislaby@gmail.com> 96 97--------------------------- 98 99What: The ieee80211_regdom module parameter 100When: March 2010 / desktop catchup 101 102Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code, 103 and currently serves as an option for users to define an 104 ISO / IEC 3166 alpha2 code for the country they are currently 105 present in. Although there are userspace API replacements for this 106 through nl80211 distributions haven't yet caught up with implementing 107 decent alternatives through standard GUIs. Although available as an 108 option through iw or wpa_supplicant its just a matter of time before 109 distributions pick up good GUI options for this. The ideal solution 110 would actually consist of intelligent designs which would do this for 111 the user automatically even when travelling through different countries. 112 Until then we leave this module parameter as a compromise. 113 114 When userspace improves with reasonable widely-available alternatives for 115 this we will no longer need this module parameter. This entry hopes that 116 by the super-futuristically looking date of "March 2010" we will have 117 such replacements widely available. 118 119Who: Luis R. Rodriguez <lrodriguez@atheros.com> 120 121--------------------------- 122 123What: dev->power.power_state 124When: July 2007 125Why: Broken design for runtime control over driver power states, confusing 126 driver-internal runtime power management with: mechanisms to support 127 system-wide sleep state transitions; event codes that distinguish 128 different phases of swsusp "sleep" transitions; and userspace policy 129 inputs. This framework was never widely used, and most attempts to 130 use it were broken. Drivers should instead be exposing domain-specific 131 interfaces either to kernel or to userspace. 132Who: Pavel Machek <pavel@ucw.cz> 133 134--------------------------- 135 136What: /proc/<pid>/oom_adj 137When: August 2012 138Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's 139 badness heuristic used to determine which task to kill when the kernel 140 is out of memory. 141 142 The badness heuristic has since been rewritten since the introduction of 143 this tunable such that its meaning is deprecated. The value was 144 implemented as a bitshift on a score generated by the badness() 145 function that did not have any precise units of measure. With the 146 rewrite, the score is given as a proportion of available memory to the 147 task allocating pages, so using a bitshift which grows the score 148 exponentially is, thus, impossible to tune with fine granularity. 149 150 A much more powerful interface, /proc/<pid>/oom_score_adj, was 151 introduced with the oom killer rewrite that allows users to increase or 152 decrease the badness score linearly. This interface will replace 153 /proc/<pid>/oom_adj. 154 155 A warning will be emitted to the kernel log if an application uses this 156 deprecated interface. After it is printed once, future warnings will be 157 suppressed until the kernel is rebooted. 158 159--------------------------- 160 161What: remove EXPORT_SYMBOL(kernel_thread) 162When: August 2006 163Files: arch/*/kernel/*_ksyms.c 164Check: kernel_thread 165Why: kernel_thread is a low-level implementation detail. Drivers should 166 use the <linux/kthread.h> API instead which shields them from 167 implementation details and provides a higherlevel interface that 168 prevents bugs and code duplication 169Who: Christoph Hellwig <hch@lst.de> 170 171--------------------------- 172 173What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports 174 (temporary transition config option provided until then) 175 The transition config option will also be removed at the same time. 176When: before 2.6.19 177Why: Unused symbols are both increasing the size of the kernel binary 178 and are often a sign of "wrong API" 179Who: Arjan van de Ven <arjan@linux.intel.com> 180 181--------------------------- 182 183What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment 184When: October 2008 185Why: The stacking of class devices makes these values misleading and 186 inconsistent. 187 Class devices should not carry any of these properties, and bus 188 devices have SUBSYTEM and DRIVER as a replacement. 189Who: Kay Sievers <kay.sievers@suse.de> 190 191--------------------------- 192 193What: ACPI procfs interface 194When: July 2008 195Why: ACPI sysfs conversion should be finished by January 2008. 196 ACPI procfs interface will be removed in July 2008 so that 197 there is enough time for the user space to catch up. 198Who: Zhang Rui <rui.zhang@intel.com> 199 200--------------------------- 201 202What: CONFIG_ACPI_PROCFS_POWER 203When: 2.6.39 204Why: sysfs I/F for ACPI power devices, including AC and Battery, 205 has been working in upstream kernel since 2.6.24, Sep 2007. 206 In 2.6.37, we make the sysfs I/F always built in and this option 207 disabled by default. 208 Remove this option and the ACPI power procfs interface in 2.6.39. 209Who: Zhang Rui <rui.zhang@intel.com> 210 211--------------------------- 212 213What: /proc/acpi/event 214When: February 2008 215Why: /proc/acpi/event has been replaced by events via the input layer 216 and netlink since 2.6.23. 217Who: Len Brown <len.brown@intel.com> 218 219--------------------------- 220 221What: i386/x86_64 bzImage symlinks 222When: April 2010 223 224Why: The i386/x86_64 merge provides a symlink to the old bzImage 225 location so not yet updated user space tools, e.g. package 226 scripts, do not break. 227Who: Thomas Gleixner <tglx@linutronix.de> 228 229--------------------------- 230 231What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib 232When: February 2010 233Why: All callers should use explicit gpio_request()/gpio_free(). 234 The autorequest mechanism in gpiolib was provided mostly as a 235 migration aid for legacy GPIO interfaces (for SOC based GPIOs). 236 Those users have now largely migrated. Platforms implementing 237 the GPIO interfaces without using gpiolib will see no changes. 238Who: David Brownell <dbrownell@users.sourceforge.net> 239--------------------------- 240 241What: b43 support for firmware revision < 410 242When: The schedule was July 2008, but it was decided that we are going to keep the 243 code as long as there are no major maintanance headaches. 244 So it _could_ be removed _any_ time now, if it conflicts with something new. 245Why: The support code for the old firmware hurts code readability/maintainability 246 and slightly hurts runtime performance. Bugfixes for the old firmware 247 are not provided by Broadcom anymore. 248Who: Michael Buesch <m@bues.ch> 249 250--------------------------- 251 252What: Ability for non root users to shm_get hugetlb pages based on mlock 253 resource limits 254When: 2.6.31 255Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or 256 have CAP_IPC_LOCK to be able to allocate shm segments backed by 257 huge pages. The mlock based rlimit check to allow shm hugetlb is 258 inconsistent with mmap based allocations. Hence it is being 259 deprecated. 260Who: Ravikiran Thirumalai <kiran@scalex86.org> 261 262--------------------------- 263 264What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS 265 (in net/core/net-sysfs.c) 266When: After the only user (hal) has seen a release with the patches 267 for enough time, probably some time in 2010. 268Why: Over 1K .text/.data size reduction, data is available in other 269 ways (ioctls) 270Who: Johannes Berg <johannes@sipsolutions.net> 271 272--------------------------- 273 274What: sysfs ui for changing p4-clockmod parameters 275When: September 2009 276Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and 277 e088e4c9cdb618675874becb91b2fd581ee707e6. 278 Removal is subject to fixing any remaining bugs in ACPI which may 279 cause the thermal throttling not to happen at the right time. 280Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com> 281 282----------------------------- 283 284What: fakephp and associated sysfs files in /sys/bus/pci/slots/ 285When: 2011 286Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to 287 represent a machine's physical PCI slots. The change in semantics 288 had userspace implications, as the hotplug core no longer allowed 289 drivers to create multiple sysfs files per physical slot (required 290 for multi-function devices, e.g.). fakephp was seen as a developer's 291 tool only, and its interface changed. Too late, we learned that 292 there were some users of the fakephp interface. 293 294 In 2.6.30, the original fakephp interface was restored. At the same 295 time, the PCI core gained the ability that fakephp provided, namely 296 function-level hot-remove and hot-add. 297 298 Since the PCI core now provides the same functionality, exposed in: 299 300 /sys/bus/pci/rescan 301 /sys/bus/pci/devices/.../remove 302 /sys/bus/pci/devices/.../rescan 303 304 there is no functional reason to maintain fakephp as well. 305 306 We will keep the existing module so that 'modprobe fakephp' will 307 present the old /sys/bus/pci/slots/... interface for compatibility, 308 but users are urged to migrate their applications to the API above. 309 310 After a reasonable transition period, we will remove the legacy 311 fakephp interface. 312Who: Alex Chiang <achiang@hp.com> 313 314--------------------------- 315 316What: CONFIG_RFKILL_INPUT 317When: 2.6.33 318Why: Should be implemented in userspace, policy daemon. 319Who: Johannes Berg <johannes@sipsolutions.net> 320 321---------------------------- 322 323What: sound-slot/service-* module aliases and related clutters in 324 sound/sound_core.c 325When: August 2010 326Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR 327 (14) and requests modules using custom sound-slot/service-* 328 module aliases. The only benefit of doing this is allowing 329 use of custom module aliases which might as well be considered 330 a bug at this point. This preemptive claiming prevents 331 alternative OSS implementations. 332 333 Till the feature is removed, the kernel will be requesting 334 both sound-slot/service-* and the standard char-major-* module 335 aliases and allow turning off the pre-claiming selectively via 336 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss 337 kernel parameter. 338 339 After the transition phase is complete, both the custom module 340 aliases and switches to disable it will go away. This removal 341 will also allow making ALSA OSS emulation independent of 342 sound_core. The dependency will be broken then too. 343Who: Tejun Heo <tj@kernel.org> 344 345---------------------------- 346 347What: sysfs-class-rfkill state file 348When: Feb 2014 349Files: net/rfkill/core.c 350Why: Documented as obsolete since Feb 2010. This file is limited to 3 351 states while the rfkill drivers can have 4 states. 352Who: anybody or Florian Mickler <florian@mickler.org> 353 354---------------------------- 355 356What: sysfs-class-rfkill claim file 357When: Feb 2012 358Files: net/rfkill/core.c 359Why: It is not possible to claim an rfkill driver since 2007. This is 360 Documented as obsolete since Feb 2010. 361Who: anybody or Florian Mickler <florian@mickler.org> 362 363---------------------------- 364 365What: KVM paravirt mmu host support 366When: January 2011 367Why: The paravirt mmu host support is slower than non-paravirt mmu, both 368 on newer and older hardware. It is already not exposed to the guest, 369 and kept only for live migration purposes. 370Who: Avi Kivity <avi@redhat.com> 371 372---------------------------- 373 374What: iwlwifi 50XX module parameters 375When: 3.0 376Why: The "..50" modules parameters were used to configure 5000 series and 377 up devices; different set of module parameters also available for 4965 378 with same functionalities. Consolidate both set into single place 379 in drivers/net/wireless/iwlwifi/iwl-agn.c 380 381Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 382 383---------------------------- 384 385What: iwl4965 alias support 386When: 3.0 387Why: Internal alias support has been present in module-init-tools for some 388 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed 389 with no impact. 390 391Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 392 393--------------------------- 394 395What: xt_NOTRACK 396Files: net/netfilter/xt_NOTRACK.c 397When: April 2011 398Why: Superseded by xt_CT 399Who: Netfilter developer team <netfilter-devel@vger.kernel.org> 400 401---------------------------- 402 403What: IRQF_DISABLED 404When: 2.6.36 405Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled 406Who: Thomas Gleixner <tglx@linutronix.de> 407 408---------------------------- 409 410What: PCI DMA unmap state API 411When: August 2012 412Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced 413 with DMA unmap state API (DMA unmap state API can be used for 414 any bus). 415Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> 416 417---------------------------- 418 419What: iwlwifi disable_hw_scan module parameters 420When: 3.0 421Why: Hareware scan is the prefer method for iwlwifi devices for 422 scanning operation. Remove software scan support for all the 423 iwlwifi devices. 424 425Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 426 427---------------------------- 428 429What: Legacy, non-standard chassis intrusion detection interface. 430When: June 2011 431Why: The adm9240, w83792d and w83793 hardware monitoring drivers have 432 legacy interfaces for chassis intrusion detection. A standard 433 interface has been added to each driver, so the legacy interface 434 can be removed. 435Who: Jean Delvare <khali@linux-fr.org> 436 437---------------------------- 438 439What: xt_connlimit rev 0 440When: 2012 441Who: Jan Engelhardt <jengelh@medozas.de> 442Files: net/netfilter/xt_connlimit.c 443 444---------------------------- 445 446What: ipt_addrtype match include file 447When: 2012 448Why: superseded by xt_addrtype 449Who: Florian Westphal <fw@strlen.de> 450Files: include/linux/netfilter_ipv4/ipt_addrtype.h 451 452---------------------------- 453 454What: i2c_driver.attach_adapter 455 i2c_driver.detach_adapter 456When: September 2011 457Why: These legacy callbacks should no longer be used as i2c-core offers 458 a variety of preferable alternative ways to instantiate I2C devices. 459Who: Jean Delvare <khali@linux-fr.org> 460 461---------------------------- 462 463What: Support for driver specific ioctls in the pwc driver (everything 464 defined in media/pwc-ioctl.h) 465When: 3.3 466Why: This stems from the v4l1 era, with v4l2 everything can be done with 467 standardized v4l2 API calls 468Who: Hans de Goede <hdegoede@redhat.com> 469 470---------------------------- 471 472What: Driver specific sysfs API in the pwc driver 473When: 3.3 474Why: Setting pan/tilt should be done with v4l2 controls, like with other 475 cams. The button is available as a standard input device 476Who: Hans de Goede <hdegoede@redhat.com> 477 478---------------------------- 479 480What: Driver specific use of pixfmt.priv in the pwc driver 481When: 3.3 482Why: The .priv field never was intended for this, setting a framerate is 483 support using the standardized S_PARM ioctl 484Who: Hans de Goede <hdegoede@redhat.com> 485 486---------------------------- 487 488What: Software emulation of arbritary resolutions in the pwc driver 489When: 3.3 490Why: The pwc driver claims to support any resolution between 160x120 491 and 640x480, but emulates this by simply drawing a black border 492 around the image. Userspace can draw its own black border if it 493 really wants one. 494Who: Hans de Goede <hdegoede@redhat.com> 495 496---------------------------- 497 498What: For VIDIOC_S_FREQUENCY the type field must match the device node's type. 499 If not, return -EINVAL. 500When: 3.2 501Why: It makes no sense to switch the tuner to radio mode by calling 502 VIDIOC_S_FREQUENCY on a video node, or to switch the tuner to tv mode by 503 calling VIDIOC_S_FREQUENCY on a radio node. This is the first step of a 504 move to more consistent handling of tv and radio tuners. 505Who: Hans Verkuil <hans.verkuil@cisco.com> 506 507---------------------------- 508 509What: Opening a radio device node will no longer automatically switch the 510 tuner mode from tv to radio. 511When: 3.3 512Why: Just opening a V4L device should not change the state of the hardware 513 like that. It's very unexpected and against the V4L spec. Instead, you 514 switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second 515 and last step of the move to consistent handling of tv and radio tuners. 516Who: Hans Verkuil <hans.verkuil@cisco.com> 517 518---------------------------- 519 520What: g_file_storage driver 521When: 3.8 522Why: This driver has been superseded by g_mass_storage. 523Who: Alan Stern <stern@rowland.harvard.edu> 524 525---------------------------- 526 527What: threeg and interface sysfs files in /sys/devices/platform/acer-wmi 528When: 2012 529Why: In 3.0, we can now autodetect internal 3G device and already have 530 the threeg rfkill device. So, we plan to remove threeg sysfs support 531 for it's no longer necessary. 532 533 We also plan to remove interface sysfs file that exposed which ACPI-WMI 534 interface that was used by acer-wmi driver. It will replaced by 535 information log when acer-wmi initial. 536Who: Lee, Chun-Yi <jlee@novell.com> 537 538---------------------------- 539 540What: The XFS nodelaylog mount option 541When: 3.3 542Why: The delaylog mode that has been the default since 2.6.39 has proven 543 stable, and the old code is in the way of additional improvements in 544 the log code. 545Who: Christoph Hellwig <hch@lst.de> 546 547---------------------------- 548 549What: iwlagn alias support 550When: 3.5 551Why: The iwlagn module has been renamed iwlwifi. The alias will be around 552 for backward compatibility for several cycles and then dropped. 553Who: Don Fry <donald.h.fry@intel.com> 554