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Documentation / feature-removal-schedule.txt




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Based on kernel version 3.6.1. Page generated on 2012-10-11 09:35 EST.

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.  The suggested deprecation period is 3 releases.
6	
7	---------------------------
8	
9	What:	ddebug_query="query" boot cmdline param
10	When:	v3.8
11	Why:	obsoleted by dyndbg="query" and module.dyndbg="query"
12	Who:	Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com>
13	
14	---------------------------
15	
16	What: /proc/sys/vm/nr_pdflush_threads
17	When: 2012
18	Why: Since pdflush is deprecated, the interface exported in /proc/sys/vm/
19	     should be removed.
20	Who: Wanpeng Li <liwp@linux.vnet.ibm.com>
21	
22	---------------------------
23	
24	What:	CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
25	When:	2012
26	Why:	This optional sub-feature of APM is of dubious reliability,
27		and ancient APM laptops are likely better served by calling HLT.
28		Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
29		the pm_idle function pointer to modules.
30	Who:	Len Brown <len.brown@intel.com>
31	
32	----------------------------
33	
34	What:	x86_32 "no-hlt" cmdline param
35	When:	2012
36	Why:	remove a branch from idle path, simplify code used by everybody.
37		This option disabled the use of HLT in idle and machine_halt()
38		for hardware that was flakey 15-years ago.  Today we have
39		"idle=poll" that removed HLT from idle, and so if such a machine
40		is still running the upstream kernel, "idle=poll" is likely sufficient.
41	Who:	Len Brown <len.brown@intel.com>
42	
43	----------------------------
44	
45	What:	x86 "idle=mwait" cmdline param
46	When:	2012
47	Why:	simplify x86 idle code
48	Who:	Len Brown <len.brown@intel.com>
49	
50	----------------------------
51	
52	What:	PRISM54
53	When:	2.6.34
54	
55	Why:	prism54 FullMAC PCI / Cardbus devices used to be supported only by the
56		prism54 wireless driver. After Intersil stopped selling these
57		devices in preference for the newer more flexible SoftMAC devices
58		a SoftMAC device driver was required and prism54 did not support
59		them. The p54pci driver now exists and has been present in the kernel for
60		a while. This driver supports both SoftMAC devices and FullMAC devices.
61		The main difference between these devices was the amount of memory which
62		could be used for the firmware. The SoftMAC devices support a smaller
63		amount of memory. Because of this the SoftMAC firmware fits into FullMAC
64		devices's memory. p54pci supports not only PCI / Cardbus but also USB
65		and SPI. Since p54pci supports all devices prism54 supports
66		you will have a conflict. I'm not quite sure how distributions are
67		handling this conflict right now. prism54 was kept around due to
68		claims users may experience issues when using the SoftMAC driver.
69		Time has passed users have not reported issues. If you use prism54
70		and for whatever reason you cannot use p54pci please let us know!
71		E-mail us at: linux-wireless@vger.kernel.org
72	
73		For more information see the p54 wiki page:
74	
75		http://wireless.kernel.org/en/users/Drivers/p54
76	
77	Who:	Luis R. Rodriguez <lrodriguez@atheros.com>
78	
79	---------------------------
80	
81	What:	The ieee80211_regdom module parameter
82	When:	March 2010 / desktop catchup
83	
84	Why:	This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
85		and currently serves as an option for users to define an
86		ISO / IEC 3166 alpha2 code for the country they are currently
87		present in. Although there are userspace API replacements for this
88		through nl80211 distributions haven't yet caught up with implementing
89		decent alternatives through standard GUIs. Although available as an
90		option through iw or wpa_supplicant its just a matter of time before
91		distributions pick up good GUI options for this. The ideal solution
92		would actually consist of intelligent designs which would do this for
93		the user automatically even when travelling through different countries.
94		Until then we leave this module parameter as a compromise.
95	
96		When userspace improves with reasonable widely-available alternatives for
97		this we will no longer need this module parameter. This entry hopes that
98		by the super-futuristically looking date of "March 2010" we will have
99		such replacements widely available.
100	
101	Who:	Luis R. Rodriguez <lrodriguez@atheros.com>
102	
103	---------------------------
104	
105	What:	dev->power.power_state
106	When:	July 2007
107	Why:	Broken design for runtime control over driver power states, confusing
108		driver-internal runtime power management with:  mechanisms to support
109		system-wide sleep state transitions; event codes that distinguish
110		different phases of swsusp "sleep" transitions; and userspace policy
111		inputs.  This framework was never widely used, and most attempts to
112		use it were broken.  Drivers should instead be exposing domain-specific
113		interfaces either to kernel or to userspace.
114	Who:	Pavel Machek <pavel@ucw.cz>
115	
116	---------------------------
117	
118	What:	/proc/<pid>/oom_adj
119	When:	August 2012
120	Why:	/proc/<pid>/oom_adj allows userspace to influence the oom killer's
121		badness heuristic used to determine which task to kill when the kernel
122		is out of memory.
123	
124		The badness heuristic has since been rewritten since the introduction of
125		this tunable such that its meaning is deprecated.  The value was
126		implemented as a bitshift on a score generated by the badness()
127		function that did not have any precise units of measure.  With the
128		rewrite, the score is given as a proportion of available memory to the
129		task allocating pages, so using a bitshift which grows the score
130		exponentially is, thus, impossible to tune with fine granularity.
131	
132		A much more powerful interface, /proc/<pid>/oom_score_adj, was
133		introduced with the oom killer rewrite that allows users to increase or
134		decrease the badness score linearly.  This interface will replace
135		/proc/<pid>/oom_adj.
136	
137		A warning will be emitted to the kernel log if an application uses this
138		deprecated interface.  After it is printed once, future warnings will be
139		suppressed until the kernel is rebooted.
140	
141	---------------------------
142	
143	What:	remove EXPORT_SYMBOL(kernel_thread)
144	When:	August 2006
145	Files:	arch/*/kernel/*_ksyms.c
146	Check:	kernel_thread
147	Why:	kernel_thread is a low-level implementation detail.  Drivers should
148	        use the <linux/kthread.h> API instead which shields them from
149		implementation details and provides a higherlevel interface that
150		prevents bugs and code duplication
151	Who:	Christoph Hellwig <hch@lst.de>
152	
153	---------------------------
154	
155	What:	Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
156		(temporary transition config option provided until then)
157		The transition config option will also be removed at the same time.
158	When:	before 2.6.19
159	Why:	Unused symbols are both increasing the size of the kernel binary
160		and are often a sign of "wrong API"
161	Who:	Arjan van de Ven <arjan@linux.intel.com>
162	
163	---------------------------
164	
165	What:	PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
166	When:	October 2008
167	Why:	The stacking of class devices makes these values misleading and
168		inconsistent.
169		Class devices should not carry any of these properties, and bus
170		devices have SUBSYTEM and DRIVER as a replacement.
171	Who:	Kay Sievers <kay.sievers@suse.de>
172	
173	---------------------------
174	
175	What:	ACPI procfs interface
176	When:	July 2008
177	Why:	ACPI sysfs conversion should be finished by January 2008.
178		ACPI procfs interface will be removed in July 2008 so that
179		there is enough time for the user space to catch up.
180	Who:	Zhang Rui <rui.zhang@intel.com>
181	
182	---------------------------
183	
184	What:	CONFIG_ACPI_PROCFS_POWER
185	When:	2.6.39
186	Why:	sysfs I/F for ACPI power devices, including AC and Battery,
187	        has been working in upstream kernel since 2.6.24, Sep 2007.
188		In 2.6.37, we make the sysfs I/F always built in and this option
189		disabled by default.
190		Remove this option and the ACPI power procfs interface in 2.6.39.
191	Who:	Zhang Rui <rui.zhang@intel.com>
192	
193	---------------------------
194	
195	What:	/proc/acpi/event
196	When:	February 2008
197	Why:	/proc/acpi/event has been replaced by events via the input layer
198		and netlink since 2.6.23.
199	Who:	Len Brown <len.brown@intel.com>
200	
201	---------------------------
202	
203	What:	i386/x86_64 bzImage symlinks
204	When:	April 2010
205	
206	Why:	The i386/x86_64 merge provides a symlink to the old bzImage
207		location so not yet updated user space tools, e.g. package
208		scripts, do not break.
209	Who:	Thomas Gleixner <tglx@linutronix.de>
210	
211	---------------------------
212	
213	What:	GPIO autorequest on gpio_direction_{input,output}() in gpiolib
214	When:	February 2010
215	Why:	All callers should use explicit gpio_request()/gpio_free().
216		The autorequest mechanism in gpiolib was provided mostly as a
217		migration aid for legacy GPIO interfaces (for SOC based GPIOs).
218		Those users have now largely migrated.  Platforms implementing
219		the GPIO interfaces without using gpiolib will see no changes.
220	Who:	David Brownell <dbrownell@users.sourceforge.net>
221	---------------------------
222	
223	What:	b43 support for firmware revision < 410
224	When:	The schedule was July 2008, but it was decided that we are going to keep the
225	        code as long as there are no major maintanance headaches.
226		So it _could_ be removed _any_ time now, if it conflicts with something new.
227	Why:	The support code for the old firmware hurts code readability/maintainability
228		and slightly hurts runtime performance. Bugfixes for the old firmware
229		are not provided by Broadcom anymore.
230	Who:	Michael Buesch <m@bues.ch>
231	
232	---------------------------
233	
234	What:	Ability for non root users to shm_get hugetlb pages based on mlock
235		resource limits
236	When:	2.6.31
237	Why:	Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
238		have CAP_IPC_LOCK to be able to allocate shm segments backed by
239		huge pages.  The mlock based rlimit check to allow shm hugetlb is
240		inconsistent with mmap based allocations.  Hence it is being
241		deprecated.
242	Who:	Ravikiran Thirumalai <kiran@scalex86.org>
243	
244	---------------------------
245	
246	What:	sysfs ui for changing p4-clockmod parameters
247	When:	September 2009
248	Why:	See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
249		e088e4c9cdb618675874becb91b2fd581ee707e6.
250		Removal is subject to fixing any remaining bugs in ACPI which may
251		cause the thermal throttling not to happen at the right time.
252	Who:	Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
253	
254	-----------------------------
255	
256	What:	fakephp and associated sysfs files in /sys/bus/pci/slots/
257	When:	2011
258	Why:	In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
259		represent a machine's physical PCI slots. The change in semantics
260		had userspace implications, as the hotplug core no longer allowed
261		drivers to create multiple sysfs files per physical slot (required
262		for multi-function devices, e.g.). fakephp was seen as a developer's
263		tool only, and its interface changed. Too late, we learned that
264		there were some users of the fakephp interface.
265	
266		In 2.6.30, the original fakephp interface was restored. At the same
267		time, the PCI core gained the ability that fakephp provided, namely
268		function-level hot-remove and hot-add.
269	
270		Since the PCI core now provides the same functionality, exposed in:
271	
272			/sys/bus/pci/rescan
273			/sys/bus/pci/devices/.../remove
274			/sys/bus/pci/devices/.../rescan
275	
276		there is no functional reason to maintain fakephp as well.
277	
278		We will keep the existing module so that 'modprobe fakephp' will
279		present the old /sys/bus/pci/slots/... interface for compatibility,
280		but users are urged to migrate their applications to the API above.
281	
282		After a reasonable transition period, we will remove the legacy
283		fakephp interface.
284	Who:	Alex Chiang <achiang@hp.com>
285	
286	---------------------------
287	
288	What:	CONFIG_RFKILL_INPUT
289	When:	2.6.33
290	Why:	Should be implemented in userspace, policy daemon.
291	Who:	Johannes Berg <johannes@sipsolutions.net>
292	
293	----------------------------
294	
295	What:	sound-slot/service-* module aliases and related clutters in
296		sound/sound_core.c
297	When:	August 2010
298	Why:	OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
299		(14) and requests modules using custom sound-slot/service-*
300		module aliases.  The only benefit of doing this is allowing
301		use of custom module aliases which might as well be considered
302		a bug at this point.  This preemptive claiming prevents
303		alternative OSS implementations.
304	
305		Till the feature is removed, the kernel will be requesting
306		both sound-slot/service-* and the standard char-major-* module
307		aliases and allow turning off the pre-claiming selectively via
308		CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
309		kernel parameter.
310	
311		After the transition phase is complete, both the custom module
312		aliases and switches to disable it will go away.  This removal
313		will also allow making ALSA OSS emulation independent of
314		sound_core.  The dependency will be broken then too.
315	Who:	Tejun Heo <tj@kernel.org>
316	
317	----------------------------
318	
319	What:	sysfs-class-rfkill state file
320	When:	Feb 2014
321	Files:	net/rfkill/core.c
322	Why: 	Documented as obsolete since Feb 2010. This file is limited to 3
323		states while the rfkill drivers can have 4 states.
324	Who: 	anybody or Florian Mickler <florian@mickler.org>
325	
326	----------------------------
327	
328	What: 	sysfs-class-rfkill claim file
329	When:	Feb 2012
330	Files:	net/rfkill/core.c
331	Why:	It is not possible to claim an rfkill driver since 2007. This is
332		Documented as obsolete since Feb 2010.
333	Who: 	anybody or Florian Mickler <florian@mickler.org>
334	
335	----------------------------
336	
337	What:	iwlwifi 50XX module parameters
338	When:	3.0
339	Why:	The "..50" modules parameters were used to configure 5000 series and
340		up devices; different set of module parameters also available for 4965
341		with same functionalities. Consolidate both set into single place
342		in drivers/net/wireless/iwlwifi/iwl-agn.c
343	
344	Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
345	
346	----------------------------
347	
348	What:	iwl4965 alias support
349	When:	3.0
350	Why:	Internal alias support has been present in module-init-tools for some
351		time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
352		with no impact.
353	
354	Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
355	
356	---------------------------
357	
358	What:	xt_NOTRACK
359	Files:	net/netfilter/xt_NOTRACK.c
360	When:	April 2011
361	Why:	Superseded by xt_CT
362	Who:	Netfilter developer team <netfilter-devel@vger.kernel.org>
363	
364	----------------------------
365	
366	What:	IRQF_DISABLED
367	When:	2.6.36
368	Why:	The flag is a NOOP as we run interrupt handlers with interrupts disabled
369	Who:	Thomas Gleixner <tglx@linutronix.de>
370	
371	----------------------------
372	
373	What: 	PCI DMA unmap state API
374	When:	August 2012
375	Why:	PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
376		with DMA unmap state API (DMA unmap state API can be used for
377		any bus).
378	Who:	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
379	
380	----------------------------
381	
382	What:	iwlwifi disable_hw_scan module parameters
383	When:	3.0
384	Why:	Hareware scan is the prefer method for iwlwifi devices for
385		scanning operation. Remove software scan support for all the
386		iwlwifi devices.
387	
388	Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
389	
390	----------------------------
391	
392	What:	Legacy, non-standard chassis intrusion detection interface.
393	When:	June 2011
394	Why:	The adm9240, w83792d and w83793 hardware monitoring drivers have
395		legacy interfaces for chassis intrusion detection. A standard
396		interface has been added to each driver, so the legacy interface
397		can be removed.
398	Who:	Jean Delvare <khali@linux-fr.org>
399	
400	----------------------------
401	
402	What:	i2c_driver.attach_adapter
403		i2c_driver.detach_adapter
404	When:	September 2011
405	Why:	These legacy callbacks should no longer be used as i2c-core offers
406		a variety of preferable alternative ways to instantiate I2C devices.
407	Who:	Jean Delvare <khali@linux-fr.org>
408	
409	----------------------------
410	
411	What:	Opening a radio device node will no longer automatically switch the
412		tuner mode from tv to radio.
413	When:	3.3
414	Why:	Just opening a V4L device should not change the state of the hardware
415		like that. It's very unexpected and against the V4L spec. Instead, you
416		switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second
417		and last step of the move to consistent handling of tv and radio tuners.
418	Who:	Hans Verkuil <hans.verkuil@cisco.com>
419	
420	----------------------------
421	
422	What:	CONFIG_CFG80211_WEXT
423	When:	as soon as distributions ship new wireless tools, ie. wpa_supplicant 1.0
424		and NetworkManager/connman/etc. that are able to use nl80211
425	Why:	Wireless extensions are deprecated, and userland tools are moving to
426		using nl80211. New drivers are no longer using wireless extensions,
427		and while there might still be old drivers, both new drivers and new
428		userland no longer needs them and they can't be used for an feature
429		developed in the past couple of years. As such, compatibility with
430		wireless extensions in new drivers will be removed.
431	Who:	Johannes Berg <johannes@sipsolutions.net>
432	
433	----------------------------
434	
435	What:	g_file_storage driver
436	When:	3.8
437	Why:	This driver has been superseded by g_mass_storage.
438	Who:	Alan Stern <stern@rowland.harvard.edu>
439	
440	----------------------------
441	
442	What:   threeg and interface sysfs files in /sys/devices/platform/acer-wmi
443	When:   2012
444	Why:    In 3.0, we can now autodetect internal 3G device and already have
445		the threeg rfkill device. So, we plan to remove threeg sysfs support
446		for it's no longer necessary.
447	
448		We also plan to remove interface sysfs file that exposed which ACPI-WMI
449		interface that was used by acer-wmi driver. It will replaced by
450		information log when acer-wmi initial.
451	Who:    Lee, Chun-Yi <jlee@novell.com>
452	
453	---------------------------
454	
455	What:	/sys/devices/platform/_UDC_/udc/_UDC_/is_dualspeed file and
456		is_dualspeed line in /sys/devices/platform/ci13xxx_*/udc/device file.
457	When:	3.8
458	Why:	The is_dualspeed file is superseded by maximum_speed in the same
459		directory and is_dualspeed line in device file is superseded by
460		max_speed line in the same file.
461	
462		The maximum_speed/max_speed specifies maximum speed supported by UDC.
463		To check if dualspeeed is supported, check if the value is >= 3.
464		Various possible speeds are defined in <linux/usb/ch9.h>.
465	Who:	Michal Nazarewicz <mina86@mina86.com>
466	
467	----------------------------
468	
469	What:	The XFS nodelaylog mount option
470	When:	3.3
471	Why:	The delaylog mode that has been the default since 2.6.39 has proven
472		stable, and the old code is in the way of additional improvements in
473		the log code.
474	Who:	Christoph Hellwig <hch@lst.de>
475	
476	----------------------------
477	
478	What:	iwlagn alias support
479	When:	3.5
480	Why:	The iwlagn module has been renamed iwlwifi.  The alias will be around
481		for backward compatibility for several cycles and then dropped.
482	Who:	Don Fry <donald.h.fry@intel.com>
483	
484	----------------------------
485	
486	What:	pci_scan_bus_parented()
487	When:	3.5
488	Why:	The pci_scan_bus_parented() interface creates a new root bus.  The
489		bus is created with default resources (ioport_resource and
490		iomem_resource) that are always wrong, so we rely on arch code to
491		correct them later.  Callers of pci_scan_bus_parented() should
492		convert to using pci_scan_root_bus() so they can supply a list of
493		bus resources when the bus is created.
494	Who:	Bjorn Helgaas <bhelgaas@google.com>
495	
496	----------------------------
497	
498	What:	Low Performance USB Block driver ("CONFIG_BLK_DEV_UB")
499	When:	3.6
500	Why:	This driver provides support for USB storage devices like "USB
501		sticks". As of now, it is deactivated in Debian, Fedora and
502	        Ubuntu. All current users can switch over to usb-storage
503	        (CONFIG_USB_STORAGE) which only drawback is the additional SCSI
504	        stack.
505	Who:	Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
506	
507	----------------------------
508	
509	What:	get_robust_list syscall
510	When:	2013
511	Why:	There appear to be no production users of the get_robust_list syscall,
512		and it runs the risk of leaking address locations, allowing the bypass
513		of ASLR. It was only ever intended for debugging, so it should be
514		removed.
515	Who:	Kees Cook <keescook@chromium.org>
516	
517	----------------------------
518	
519	What:	Removing the pn544 raw driver.
520	When:	3.6
521	Why:	With the introduction of the NFC HCI and SHDL kernel layers, pn544.c
522		is being replaced by pn544_hci.c which is accessible through the netlink
523		and socket NFC APIs. Moreover, pn544.c is outdated and does not seem to
524		work properly with the latest Android stacks.
525		Having 2 drivers for the same hardware is confusing and as such we
526		should only keep the one following the kernel NFC APIs.
527	Who:	Samuel Ortiz <sameo@linux.intel.com>
528	
529	----------------------------
530	
531	What:	setitimer accepts user NULL pointer (value)
532	When:	3.6
533	Why:	setitimer is not returning -EFAULT if user pointer is NULL. This
534		violates the spec.
535	Who:	Sasikantha Babu <sasikanth.v19@gmail.com>
536	
537	----------------------------
538	
539	What:	remove bogus DV presets V4L2_DV_1080I29_97, V4L2_DV_1080I30 and
540		V4L2_DV_1080I25
541	When:	3.6
542	Why:	These HDTV formats do not exist and were added by a confused mind
543		(that was me, to be precise...)
544	Who:	Hans Verkuil <hans.verkuil@cisco.com>
545	
546	----------------------------
547	
548	What:	V4L2_CID_HCENTER, V4L2_CID_VCENTER V4L2 controls
549	When:	3.7
550	Why:	The V4L2_CID_VCENTER, V4L2_CID_HCENTER controls have been deprecated
551		for about 4 years and they are not used by any mainline driver.
552		There are newer controls (V4L2_CID_PAN*, V4L2_CID_TILT*) that provide
553		similar	functionality.
554	Who:	Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
555	
556	----------------------------
557	
558	What:	cgroup option updates via remount
559	When:	March 2013
560	Why:	Remount currently allows changing bound subsystems and
561		release_agent.  Rebinding is hardly useful as it only works
562		when the hierarchy is empty and release_agent itself should be
563		replaced with conventional fsnotify.
564	
565	----------------------------
566	
567	What:  xt_recent rev 0
568	When:  2013
569	Who:   Pablo Neira Ayuso <pablo@netfilter.org>
570	Files: net/netfilter/xt_recent.c
571	
572	----------------------------
573	
574	What:	KVM debugfs statistics
575	When:	2013
576	Why:	KVM tracepoints provide mostly equivalent information in a much more
577	        flexible fashion.
578	
579	----------------------------
580	
581	What:	at91-mci driver ("CONFIG_MMC_AT91")
582	When:	3.8
583	Why:	There are two mci drivers: at91-mci and atmel-mci. The PDC support
584		was added to atmel-mci as a first step to support more chips.
585		Then at91-mci was kept only for old IP versions (on at91rm9200 and
586		at91sam9261). The support of these IP versions has just been added
587		to atmel-mci, so atmel-mci can be used for all chips.
588	Who:	Ludovic Desroches <ludovic.desroches@atmel.com>
589	
590	----------------------------
591	
592	What:	net/wanrouter/
593	When:	June 2013
594	Why:	Unsupported/unmaintained/unused since 2.6
595	
596	----------------------------
597	
598	What:	V4L2 selections API target rectangle and flags unification, the
599		following definitions will be removed: V4L2_SEL_TGT_CROP_ACTIVE,
600		V4L2_SEL_TGT_COMPOSE_ACTIVE, V4L2_SUBDEV_SEL_*, V4L2_SUBDEV_SEL_FLAG_*
601		in favor of common V4L2_SEL_TGT_* and V4L2_SEL_FLAG_* definitions.
602		For more details see include/linux/v4l2-common.h.
603	When:	3.8
604	Why:	The regular V4L2 selections and the subdev selection API originally
605		defined distinct names for the target rectangles and flags - V4L2_SEL_*
606		and V4L2_SUBDEV_SEL_*. Although, it turned out that the meaning of these
607		target rectangles is virtually identical and the APIs were consolidated
608		to use single set of names - V4L2_SEL_*. This didn't involve any ABI
609		changes. Alias definitions were created for the original ones to avoid
610		any instabilities in the user space interface. After few cycles these
611		backward compatibility definitions will be removed.
612	Who:	Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
613	
614	----------------------------
615	
616	What:	Using V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT flags
617		to indicate a V4L2 memory-to-memory device capability
618	When:	3.8
619	Why:	New drivers should use new V4L2_CAP_VIDEO_M2M capability flag
620		to indicate a V4L2 video memory-to-memory (M2M) device and
621		applications can now identify a M2M video device by checking
622		for V4L2_CAP_VIDEO_M2M, with VIDIOC_QUERYCAP ioctl. Using ORed
623		V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT flags for M2M
624		devices is ambiguous and may lead, for example, to identifying
625		a M2M device as a video	capture or output device.
626	Who:	Sylwester Nawrocki <s.nawrocki@samsung.com>
627	
628	----------------------------
629	
630	What:	OMAP private DMA implementation
631	When:	2013
632	Why:	We have a DMA engine implementation; all users should be updated
633		to use this rather than persisting with the old APIs.  The old APIs
634		block merging the old DMA engine implementation into the DMA
635		engine driver.
636	Who:	Russell King <linux@arm.linux.org.uk>,
637		Santosh Shilimkar <santosh.shilimkar@ti.com>
638	
639	----------------------------
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