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: The ieee80211_regdom module parameter 89When: March 2010 / desktop catchup 90 91Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code, 92 and currently serves as an option for users to define an 93 ISO / IEC 3166 alpha2 code for the country they are currently 94 present in. Although there are userspace API replacements for this 95 through nl80211 distributions haven't yet caught up with implementing 96 decent alternatives through standard GUIs. Although available as an 97 option through iw or wpa_supplicant its just a matter of time before 98 distributions pick up good GUI options for this. The ideal solution 99 would actually consist of intelligent designs which would do this for 100 the user automatically even when travelling through different countries. 101 Until then we leave this module parameter as a compromise. 102 103 When userspace improves with reasonable widely-available alternatives for 104 this we will no longer need this module parameter. This entry hopes that 105 by the super-futuristically looking date of "March 2010" we will have 106 such replacements widely available. 107 108Who: Luis R. Rodriguez <lrodriguez@atheros.com> 109 110--------------------------- 111 112What: dev->power.power_state 113When: July 2007 114Why: Broken design for runtime control over driver power states, confusing 115 driver-internal runtime power management with: mechanisms to support 116 system-wide sleep state transitions; event codes that distinguish 117 different phases of swsusp "sleep" transitions; and userspace policy 118 inputs. This framework was never widely used, and most attempts to 119 use it were broken. Drivers should instead be exposing domain-specific 120 interfaces either to kernel or to userspace. 121Who: Pavel Machek <pavel@ucw.cz> 122 123--------------------------- 124 125What: /proc/<pid>/oom_adj 126When: August 2012 127Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's 128 badness heuristic used to determine which task to kill when the kernel 129 is out of memory. 130 131 The badness heuristic has since been rewritten since the introduction of 132 this tunable such that its meaning is deprecated. The value was 133 implemented as a bitshift on a score generated by the badness() 134 function that did not have any precise units of measure. With the 135 rewrite, the score is given as a proportion of available memory to the 136 task allocating pages, so using a bitshift which grows the score 137 exponentially is, thus, impossible to tune with fine granularity. 138 139 A much more powerful interface, /proc/<pid>/oom_score_adj, was 140 introduced with the oom killer rewrite that allows users to increase or 141 decrease the badness score linearly. This interface will replace 142 /proc/<pid>/oom_adj. 143 144 A warning will be emitted to the kernel log if an application uses this 145 deprecated interface. After it is printed once, future warnings will be 146 suppressed until the kernel is rebooted. 147 148--------------------------- 149 150What: remove EXPORT_SYMBOL(kernel_thread) 151When: August 2006 152Files: arch/*/kernel/*_ksyms.c 153Check: kernel_thread 154Why: kernel_thread is a low-level implementation detail. Drivers should 155 use the <linux/kthread.h> API instead which shields them from 156 implementation details and provides a higherlevel interface that 157 prevents bugs and code duplication 158Who: Christoph Hellwig <hch@lst.de> 159 160--------------------------- 161 162What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports 163 (temporary transition config option provided until then) 164 The transition config option will also be removed at the same time. 165When: before 2.6.19 166Why: Unused symbols are both increasing the size of the kernel binary 167 and are often a sign of "wrong API" 168Who: Arjan van de Ven <arjan@linux.intel.com> 169 170--------------------------- 171 172What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment 173When: October 2008 174Why: The stacking of class devices makes these values misleading and 175 inconsistent. 176 Class devices should not carry any of these properties, and bus 177 devices have SUBSYTEM and DRIVER as a replacement. 178Who: Kay Sievers <kay.sievers@suse.de> 179 180--------------------------- 181 182What: ACPI procfs interface 183When: July 2008 184Why: ACPI sysfs conversion should be finished by January 2008. 185 ACPI procfs interface will be removed in July 2008 so that 186 there is enough time for the user space to catch up. 187Who: Zhang Rui <rui.zhang@intel.com> 188 189--------------------------- 190 191What: CONFIG_ACPI_PROCFS_POWER 192When: 2.6.39 193Why: sysfs I/F for ACPI power devices, including AC and Battery, 194 has been working in upstream kernel since 2.6.24, Sep 2007. 195 In 2.6.37, we make the sysfs I/F always built in and this option 196 disabled by default. 197 Remove this option and the ACPI power procfs interface in 2.6.39. 198Who: Zhang Rui <rui.zhang@intel.com> 199 200--------------------------- 201 202What: /proc/acpi/event 203When: February 2008 204Why: /proc/acpi/event has been replaced by events via the input layer 205 and netlink since 2.6.23. 206Who: Len Brown <len.brown@intel.com> 207 208--------------------------- 209 210What: i386/x86_64 bzImage symlinks 211When: April 2010 212 213Why: The i386/x86_64 merge provides a symlink to the old bzImage 214 location so not yet updated user space tools, e.g. package 215 scripts, do not break. 216Who: Thomas Gleixner <tglx@linutronix.de> 217 218--------------------------- 219 220What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib 221When: February 2010 222Why: All callers should use explicit gpio_request()/gpio_free(). 223 The autorequest mechanism in gpiolib was provided mostly as a 224 migration aid for legacy GPIO interfaces (for SOC based GPIOs). 225 Those users have now largely migrated. Platforms implementing 226 the GPIO interfaces without using gpiolib will see no changes. 227Who: David Brownell <dbrownell@users.sourceforge.net> 228--------------------------- 229 230What: b43 support for firmware revision < 410 231When: The schedule was July 2008, but it was decided that we are going to keep the 232 code as long as there are no major maintanance headaches. 233 So it _could_ be removed _any_ time now, if it conflicts with something new. 234Why: The support code for the old firmware hurts code readability/maintainability 235 and slightly hurts runtime performance. Bugfixes for the old firmware 236 are not provided by Broadcom anymore. 237Who: Michael Buesch <m@bues.ch> 238 239--------------------------- 240 241What: Ability for non root users to shm_get hugetlb pages based on mlock 242 resource limits 243When: 2.6.31 244Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or 245 have CAP_IPC_LOCK to be able to allocate shm segments backed by 246 huge pages. The mlock based rlimit check to allow shm hugetlb is 247 inconsistent with mmap based allocations. Hence it is being 248 deprecated. 249Who: Ravikiran Thirumalai <kiran@scalex86.org> 250 251--------------------------- 252 253What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS 254 (in net/core/net-sysfs.c) 255When: 3.5 256Why: Over 1K .text/.data size reduction, data is available in other 257 ways (ioctls) 258Who: Johannes Berg <johannes@sipsolutions.net> 259 260--------------------------- 261 262What: sysfs ui for changing p4-clockmod parameters 263When: September 2009 264Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and 265 e088e4c9cdb618675874becb91b2fd581ee707e6. 266 Removal is subject to fixing any remaining bugs in ACPI which may 267 cause the thermal throttling not to happen at the right time. 268Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com> 269 270----------------------------- 271 272What: fakephp and associated sysfs files in /sys/bus/pci/slots/ 273When: 2011 274Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to 275 represent a machine's physical PCI slots. The change in semantics 276 had userspace implications, as the hotplug core no longer allowed 277 drivers to create multiple sysfs files per physical slot (required 278 for multi-function devices, e.g.). fakephp was seen as a developer's 279 tool only, and its interface changed. Too late, we learned that 280 there were some users of the fakephp interface. 281 282 In 2.6.30, the original fakephp interface was restored. At the same 283 time, the PCI core gained the ability that fakephp provided, namely 284 function-level hot-remove and hot-add. 285 286 Since the PCI core now provides the same functionality, exposed in: 287 288 /sys/bus/pci/rescan 289 /sys/bus/pci/devices/.../remove 290 /sys/bus/pci/devices/.../rescan 291 292 there is no functional reason to maintain fakephp as well. 293 294 We will keep the existing module so that 'modprobe fakephp' will 295 present the old /sys/bus/pci/slots/... interface for compatibility, 296 but users are urged to migrate their applications to the API above. 297 298 After a reasonable transition period, we will remove the legacy 299 fakephp interface. 300Who: Alex Chiang <achiang@hp.com> 301 302--------------------------- 303 304What: CONFIG_RFKILL_INPUT 305When: 2.6.33 306Why: Should be implemented in userspace, policy daemon. 307Who: Johannes Berg <johannes@sipsolutions.net> 308 309---------------------------- 310 311What: sound-slot/service-* module aliases and related clutters in 312 sound/sound_core.c 313When: August 2010 314Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR 315 (14) and requests modules using custom sound-slot/service-* 316 module aliases. The only benefit of doing this is allowing 317 use of custom module aliases which might as well be considered 318 a bug at this point. This preemptive claiming prevents 319 alternative OSS implementations. 320 321 Till the feature is removed, the kernel will be requesting 322 both sound-slot/service-* and the standard char-major-* module 323 aliases and allow turning off the pre-claiming selectively via 324 CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss 325 kernel parameter. 326 327 After the transition phase is complete, both the custom module 328 aliases and switches to disable it will go away. This removal 329 will also allow making ALSA OSS emulation independent of 330 sound_core. The dependency will be broken then too. 331Who: Tejun Heo <tj@kernel.org> 332 333---------------------------- 334 335What: sysfs-class-rfkill state file 336When: Feb 2014 337Files: net/rfkill/core.c 338Why: Documented as obsolete since Feb 2010. This file is limited to 3 339 states while the rfkill drivers can have 4 states. 340Who: anybody or Florian Mickler <florian@mickler.org> 341 342---------------------------- 343 344What: sysfs-class-rfkill claim file 345When: Feb 2012 346Files: net/rfkill/core.c 347Why: It is not possible to claim an rfkill driver since 2007. This is 348 Documented as obsolete since Feb 2010. 349Who: anybody or Florian Mickler <florian@mickler.org> 350 351---------------------------- 352 353What: iwlwifi 50XX module parameters 354When: 3.0 355Why: The "..50" modules parameters were used to configure 5000 series and 356 up devices; different set of module parameters also available for 4965 357 with same functionalities. Consolidate both set into single place 358 in drivers/net/wireless/iwlwifi/iwl-agn.c 359 360Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 361 362---------------------------- 363 364What: iwl4965 alias support 365When: 3.0 366Why: Internal alias support has been present in module-init-tools for some 367 time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed 368 with no impact. 369 370Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 371 372--------------------------- 373 374What: xt_NOTRACK 375Files: net/netfilter/xt_NOTRACK.c 376When: April 2011 377Why: Superseded by xt_CT 378Who: Netfilter developer team <netfilter-devel@vger.kernel.org> 379 380---------------------------- 381 382What: IRQF_DISABLED 383When: 2.6.36 384Why: The flag is a NOOP as we run interrupt handlers with interrupts disabled 385Who: Thomas Gleixner <tglx@linutronix.de> 386 387---------------------------- 388 389What: PCI DMA unmap state API 390When: August 2012 391Why: PCI DMA unmap state API (include/linux/pci-dma.h) was replaced 392 with DMA unmap state API (DMA unmap state API can be used for 393 any bus). 394Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> 395 396---------------------------- 397 398What: iwlwifi disable_hw_scan module parameters 399When: 3.0 400Why: Hareware scan is the prefer method for iwlwifi devices for 401 scanning operation. Remove software scan support for all the 402 iwlwifi devices. 403 404Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> 405 406---------------------------- 407 408What: Legacy, non-standard chassis intrusion detection interface. 409When: June 2011 410Why: The adm9240, w83792d and w83793 hardware monitoring drivers have 411 legacy interfaces for chassis intrusion detection. A standard 412 interface has been added to each driver, so the legacy interface 413 can be removed. 414Who: Jean Delvare <khali@linux-fr.org> 415 416---------------------------- 417 418What: xt_connlimit rev 0 419When: 2012 420Who: Jan Engelhardt <jengelh@medozas.de> 421Files: net/netfilter/xt_connlimit.c 422 423---------------------------- 424 425What: ipt_addrtype match include file 426When: 2012 427Why: superseded by xt_addrtype 428Who: Florian Westphal <fw@strlen.de> 429Files: include/linux/netfilter_ipv4/ipt_addrtype.h 430 431---------------------------- 432 433What: i2c_driver.attach_adapter 434 i2c_driver.detach_adapter 435When: September 2011 436Why: These legacy callbacks should no longer be used as i2c-core offers 437 a variety of preferable alternative ways to instantiate I2C devices. 438Who: Jean Delvare <khali@linux-fr.org> 439 440---------------------------- 441 442What: Opening a radio device node will no longer automatically switch the 443 tuner mode from tv to radio. 444When: 3.3 445Why: Just opening a V4L device should not change the state of the hardware 446 like that. It's very unexpected and against the V4L spec. Instead, you 447 switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second 448 and last step of the move to consistent handling of tv and radio tuners. 449Who: Hans Verkuil <hans.verkuil@cisco.com> 450 451---------------------------- 452 453What: g_file_storage driver 454When: 3.8 455Why: This driver has been superseded by g_mass_storage. 456Who: Alan Stern <stern@rowland.harvard.edu> 457 458---------------------------- 459 460What: threeg and interface sysfs files in /sys/devices/platform/acer-wmi 461When: 2012 462Why: In 3.0, we can now autodetect internal 3G device and already have 463 the threeg rfkill device. So, we plan to remove threeg sysfs support 464 for it's no longer necessary. 465 466 We also plan to remove interface sysfs file that exposed which ACPI-WMI 467 interface that was used by acer-wmi driver. It will replaced by 468 information log when acer-wmi initial. 469Who: Lee, Chun-Yi <jlee@novell.com> 470 471--------------------------- 472 473What: /sys/devices/platform/_UDC_/udc/_UDC_/is_dualspeed file and 474 is_dualspeed line in /sys/devices/platform/ci13xxx_*/udc/device file. 475When: 3.8 476Why: The is_dualspeed file is superseded by maximum_speed in the same 477 directory and is_dualspeed line in device file is superseded by 478 max_speed line in the same file. 479 480 The maximum_speed/max_speed specifies maximum speed supported by UDC. 481 To check if dualspeeed is supported, check if the value is >= 3. 482 Various possible speeds are defined in <linux/usb/ch9.h>. 483Who: Michal Nazarewicz <mina86@mina86.com> 484 485---------------------------- 486 487What: The XFS nodelaylog mount option 488When: 3.3 489Why: The delaylog mode that has been the default since 2.6.39 has proven 490 stable, and the old code is in the way of additional improvements in 491 the log code. 492Who: Christoph Hellwig <hch@lst.de> 493 494---------------------------- 495 496What: iwlagn alias support 497When: 3.5 498Why: The iwlagn module has been renamed iwlwifi. The alias will be around 499 for backward compatibility for several cycles and then dropped. 500Who: Don Fry <donald.h.fry@intel.com> 501 502---------------------------- 503 504What: pci_scan_bus_parented() 505When: 3.5 506Why: The pci_scan_bus_parented() interface creates a new root bus. The 507 bus is created with default resources (ioport_resource and 508 iomem_resource) that are always wrong, so we rely on arch code to 509 correct them later. Callers of pci_scan_bus_parented() should 510 convert to using pci_scan_root_bus() so they can supply a list of 511 bus resources when the bus is created. 512Who: Bjorn Helgaas <bhelgaas@google.com> 513 514---------------------------- 515 516What: The CAP9 SoC family will be removed 517When: 3.4 518Files: arch/arm/mach-at91/at91cap9.c 519 arch/arm/mach-at91/at91cap9_devices.c 520 arch/arm/mach-at91/include/mach/at91cap9.h 521 arch/arm/mach-at91/include/mach/at91cap9_matrix.h 522 arch/arm/mach-at91/include/mach/at91cap9_ddrsdr.h 523 arch/arm/mach-at91/board-cap9adk.c 524Why: The code is not actively maintained and platforms are now hard to find. 525Who: Nicolas Ferre <nicolas.ferre@atmel.com> 526 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> 527