Pull drm fixes from Dave Airlie:
 "Mostly radeon, more fixes for dynamic power management which is is off
  by default for this release anyways, but there are a large number of
  testers, so I'd like to keep merging the fixes.

  Otherwise, radeon UVD fixes affecting suspend/resume regressions, i915
  regression fixes, one for your mac mini, ast, mgag200, cirrus ttm fix
  and one regression fix in the core"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (25 commits)
  drm: Don't pass negative delta to ktime_sub_ns()
  drm/radeon: make missing smc ucode non-fatal
  drm/radeon/dpm: require rlc for dpm
  drm/radeon/cik: use a mutex to properly lock srbm instanced registers
  drm/radeon: remove unnecessary unpin
  drm/radeon: add more UVD CS checking
  drm/radeon: stop sending invalid UVD destroy msg
  drm/radeon: only save UVD bo when we have open handles
  drm/radeon: always program the MC on startup
  drm/radeon: fix audio dto calculation on DCE3+ (v3)
  drm/radeon/dpm: disable sclk ss on rv6xx
  drm/radeon: fix halting UVD
  drm/radeon/dpm: adjust power state properly for UVD on SI
  drm/radeon/dpm: fix spread spectrum setup (v2)
  drm/radeon/dpm: adjust thermal protection requirements
  drm/radeon: select audio dto based on encoder id for DCE3
  drm/radeon: properly handle pm on gpu reset
  drm/i915: do not disable backlight on vgaswitcheroo switch off
  drm/i915: Don't call encoder's get_config unless encoder is active
  drm/i915: avoid brightness overflow when doing scale
  ...

device_close()->recalc_sigpending() is not needed, sigprocmask() takes
care of TIF_SIGPENDING correctly.

And without ->siglock it is racy and wrong, it can wrongly clear
TIF_SIGPENDING and miss a signal.

But even with this patch device_close() is still buggy:

  1. sigprocmask() should not be used, we have set_task_blocked(),
     but this is minor.

  2. We should never block SIGKILL or SIGSTOP, and this is what
     the code tries to do.

  3. This can't protect against SIGKILL or SIGSTOP anyway. Another
     thread can do signal_wake_up(), say, do_signal_stop() or
     complete_signal() or debugger.

  4. sigprocmask(SIG_BLOCK, allsigs) doesn't necessarily clears
     TIF_SIGPENDING, say, freezing() or ->jobctl.

  5. device_write() looks equally wrong by the same reason.

Looks like, this tries to protect some wait_event_interruptible() logic
from signals, it should be turned into uninterruptible wait.  Or we need
to implement something like signals_stop/start for such a use-case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'drm-intel-fixes-2013-08-08' of git://people.freedesktop.org/~danvet/drm-intel into drm-fixes

Daniel writes:
A few bugfixes for serious stuff and regressions. Highlight is the
reinstated hack to keep the i915 backlight on when running on an optimus
machine, this prevents black screens especially with some radeon muxed
platforms. And the patch to quiet dmesg on Linus' old mac mini ;-)

* tag 'drm-intel-fixes-2013-08-08' of git://people.freedesktop.org/~danvet/drm-intel:
  drm/i915: do not disable backlight on vgaswitcheroo switch off
  drm/i915: Don't call encoder's get_config unless encoder is active
  drm/i915: avoid brightness overflow when doing scale
  drm/i915: update last_vblank when disabling the power well
  drm/i915: fix gen4 digital port hotplug definitions

Pull AVR32 build fix from Hans-Christian Egtvedt.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/egtvedt/linux-avr32:
  avr32: boards/atngw100/mrmt.c: fix building error

Ensure that user_namespace->parent chain can't grow too much.
Currently we use the hardroded 32 as limit.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ext4 bugfixes from Ted Ts'o.

Misc ext4 fixes, delayed by Ted moving mail servers and email getting
marked as spam due to bad spf records.

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: add WARN_ON to check the length of allocated blocks
  ext4: fix retry handling in ext4_ext_truncate()
  ext4: destroy ext4_es_cachep on module unload
  ext4: make sure group number is bumped after a inode allocation race

Pull security layer fix from James Morris:
 "Smack casting fix"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  Smack: IPv6 casting error fix for 3.11

Pull regulator DT binding fixes from Mark Brown:
 "A couple of fixes to bring the DT binding documentation for Palmas
  into sync with the code"

* tag 'regulator-v3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: palmas-pmic: doc: remove ti,tstep
  regulator: palmas-pmic: doc: fix typo for sleep-mode

Pull regmap fixes from Mark Brown:
 "Two things here, one is a fix for a nasty issue where we were failing
  to sync the last register in a block when using raw writes and the
  other fixes a missing header for the !REGMAP stubs so that we don't
  rely on implicit includes in that case"

* tag 'regmap-v3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: Add missing header for !CONFIG_REGMAP stubs
  regmap: cache: Make sure to sync the last register in a block

Pull spi fix from Mark Brown:
 "Just one update for SPI, a simple fix to the davinci driver to correct
  the direction for which DMA is mapped following the dmaengine
  conversion"

* tag 'spi-v3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: spi-davinci: Fix direction in dma_map_single()

Pull virtio fixes from Rusty Russell:
 "More virtio console fixes than I'm happy with, but all real issues,
  and all CC:stable.."

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  virtio-scsi: Fix virtqueue affinity setup
  virtio: console: return -ENODEV on all read operations after unplug
  virtio: console: fix raising SIGIO after port unplug
  virtio: console: clean up port data immediately at time of unplug
  virtio: console: fix race in port_fops_open() and port unplug
  virtio: console: fix race with port unplug and open/close
  virtio/console: Add pipe_lock/unlock for splice_write
  virtio/console: Quit from splice_write if pipe->nrbufs is 0

Pull ARM SoC fixes from Kevin Hilman:
 - MSM: GPIO fixes (includes old code removal)
 - OMAP: earlyprintk regression, AM33xx cpgmac PM regression
 - OMAP5: urgent fix for potentially harmful voltage regulator values
 - Renesas: gpio-keys fix, fix SD card detection, fix shdma calculation
   error
 - STi: critical SMP boot fix
 - tegra: DTS fix for usb-phy
 - a couple MAINTAINERS updates

(Arnd is on paternity leave, Kevin is stepping up to help arm-soc
maintenance)

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  MAINTAINERS: add TI Keystone ARM platform
  MAINTAINERS: delete Srinidhi from ux500
  ARM: tegra: enable ULPI phy on Colibri T20
  ARM: STi: remove sti_secondary_start from INIT section.
  ARM: STi: Fix cpu nodes with correct device_type.
  ARM: shmobile: lager: do not annotate gpio_buttons as __initdata
  ARM: shmobile: BOCK-W: fix SDHI0 PFC settings
  shdma: fixup sh_dmae_get_partial() calculation error
  ARM: OMAP2+: hwmod: AM335x: fix cpgmac address space
  ARM: OMAP2+: hwmod: rt address space index for DT
  ARM: OMAP2+: Sync hwmod state with the pm_runtime and omap_device state
  ARM: OMAP2+: Avoid idling memory controllers with no drivers
  ARM: OMAP2+: hwmod: Fix a crash in _setup_reset() with DEBUG_LL
  ARM: dts: omap5-uevm: update optional/unused regulator configurations
  ARM: dts: omap5-uevm: fix regulator configurations mandatory for SoC
  ARM: dts: omap5-uevm: document regulator signals used on the actual board
  ARM: msm: Consolidate gpiomux for older architectures
  ARM: shmobile: armadillo800eva: Don't request GPIO 166 in board code
  ARM: msm: dts: Fix the gpio register address for msm8960

This reverts commit 318df36e.

This commit caused Steven Rostedt's hackbench runs to run out of memory
due to a leak.  As noted by Joonsoo Kim, it is buggy in the following
scenario:

 "I guess, you may set 0 to all kmem caches's cpu_partial via sysfs,
  doesn't it?

  In this case, memory leak is possible in following case.  Code flow of
  possible leak is follwing case.

   * in __slab_free()
   1. (!new.inuse || !prior) && !was_frozen
   2. !kmem_cache_debug && !prior
   3. new.frozen = 1
   4. after cmpxchg_double_slab, run the (!n) case with new.frozen=1
   5. with this patch, put_cpu_partial() doesn't do anything,
      because this cache's cpu_partial is 0
   6. return

  In step 5, leak occur"

And Steven does indeed have cpu_partial set to 0 due to RT testing.

Joonsoo is cooking up a patch, but everybody agrees that reverting this
for now is the right thing to do.
Reported-and-bisected-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

there is an additional "{", which causes building error.
Signed-off-by: Cong Ding <dinggnu@gmail.com>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

It takes an unsigned value. This happens not to blow up on 64-bit
architectures, but it does on 32-bit, causing
drm_calc_vbltimestamp_from_scanoutpos() to calculate totally bogus
timestamps for vblank events. Which in turn causes e.g. gnome-shell to
hang after a DPMS off cycle with current xf86-video-ati Git.

[airlied: regression introduced in drm: use monotonic time in drm_calc_vbltimestamp_from_scanoutpos]

Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59339
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59836Tested-by: shui yangwei <yangweix.shui@intel.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Some more radeon fixes.  Mostly dpm and uvd fixes.  Fixes hangs
with dpm on more rv6xx asics, and fixes suspend and resume with UVD.

* 'drm-fixes-3.11' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: make missing smc ucode non-fatal
  drm/radeon/dpm: require rlc for dpm
  drm/radeon/cik: use a mutex to properly lock srbm instanced registers
  drm/radeon: remove unnecessary unpin
  drm/radeon: add more UVD CS checking
  drm/radeon: stop sending invalid UVD destroy msg
  drm/radeon: only save UVD bo when we have open handles
  drm/radeon: always program the MC on startup
  drm/radeon: fix audio dto calculation on DCE3+ (v3)
  drm/radeon/dpm: disable sclk ss on rv6xx
  drm/radeon: fix halting UVD
  drm/radeon/dpm: adjust power state properly for UVD on SI
  drm/radeon/dpm: fix spread spectrum setup (v2)
  drm/radeon/dpm: adjust thermal protection requirements
  drm/radeon: select audio dto based on encoder id for DCE3
  drm/radeon: properly handle pm on gpu reset

The smc ucode is required for dpm (dynamic power
management), but if it's missing just skip dpm setup
and don't disable acceleration.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=67876Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The rlc is required for dpm to work properly, so if
the rlc ucode is missing, don't enable dpm.  Enabling
dpm without the rlc enabled can result in hangs.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

We need proper locking in the driver when accessing instanced
registers on CIK.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

We don't pin the BO on allocation, so don't unpin it on free.
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Improve error handling in case userspace sends us
an invalid command buffer.
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

We also need to check the handle.
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Otherwise just reinitialize from scratch on resume,
and so make it more likely to succeed.
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

For r6xx+ asics.  This mirrors the behavior of pre-r6xx
asics.  We need to program the MC even if something
else in startup() fails.  Failure to do so results in
an unusable GPU.

Based on a fix from: Mark Kettenis <kettenis@openbsd.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Need to set the wallclock ratio and adjust the phase
and module registers appropriately.  May fix problems
with audio timing at certain display timings.

v2: properly handle clocks below 24mhz
v3: rebase r600 changes
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Enabling spread spectrum on the engine clock
leads to hangs on some asics.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=66963Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Removing the clock/power or resetting the VCPU can cause
hangs if that happens in the middle of a register write.

Stall the memory and register bus before putting the VCPU
into reset. Keep it in reset when unloading the module or
suspending.
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

There are some hardware issue with reclocking on SI when
UVD is active, so use a stable power state when UVD is
active.  Fixes possible hangs and performance issues when
using UVD on SI.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Need to check for engine and memory clock ss separately
and only enable dynamic ss if either of them are found.

This should fix systems which have a ss table, but do
not have entries for engine or memory.  On those systems
we may enable dynamic spread spectrum without enabling
it on the engine or memory clocks which can lead to a
hang in some cases.

fixes some systems reported here:
https://bugs.freedesktop.org/show_bug.cgi?id=66963

v2: fix typo
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

On rv770 and newer, clock gating is not required
for thermal protection.  The only requirement is that
the design utilizes a thermal sensor.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

There are two audio dtos on radeon asics that you can
select between.  Normally, dto0 is used for hdmi and
dto1 for DP, but it seems that the dto is somehow
tied to the encoders on DCE3 asics.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=67435Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

When we reset the GPU, we need to properly tear
down power management before reseting the GPU and then
set it back up again after reset.  Add the missing
radeon_pm_[suspend|resume] calls to the gpu reset
function.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Merge tag 'trace-fixes-3.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Oleg Nesterov has been working hard in closing all the holes that can
  lead to race conditions between deleting an event and accessing an
  event debugfs file.  This included a fix to the debugfs system (acked
  by Greg Kroah-Hartman).  We think that all the holes have been patched
  and hopefully we don't find more.  I haven't marked all of them for
  stable because I need to examine them more to figure out how far back
  some of the changes need to go.

  Along the way, some other fixes have been made.  Alexander Z Lam fixed
  some logic where the wrong buffer was being modifed.

  Andrew Vagin found a possible corruption for machines that actually
  allocate cpumask, as a reference to one was being zeroed out by
  mistake.

  Dhaval Giani found a bad prototype when tracing is not configured.

  And I not only had some changes to help Oleg, but also finally fixed a
  long standing bug that Dave Jones and others have been hitting, where
  a module unload and reload can cause the function tracing accounting
  to get screwed up"

* tag 'trace-fixes-3.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix reset of time stamps during trace_clock changes
  tracing: Make TRACE_ITER_STOP_ON_FREE stop the correct buffer
  tracing: Fix trace_dump_stack() proto when CONFIG_TRACING is not set
  tracing: Fix fields of struct trace_iterator that are zeroed by mistake
  tracing/uprobes: Fail to unregister if probe event files are in use
  tracing/kprobes: Fail to unregister if probe event files are in use
  tracing: Add comment to describe special break case in probe_remove_event_call()
  tracing: trace_remove_event_call() should fail if call/file is in use
  debugfs: debugfs_remove_recursive() must not rely on list_empty(d_subdirs)
  ftrace: Check module functions being traced on reload
  ftrace: Consolidate some duplicate code for updating ftrace ops
  tracing: Change remove_event_file_dir() to clear "d_subdirs"->i_private
  tracing: Introduce remove_event_file_dir()
  tracing: Change f_start() to take event_mutex and verify i_private != NULL
  tracing: Change event_filter_read/write to verify i_private != NULL
  tracing: Change event_enable/disable_read() to verify i_private != NULL
  tracing: Turn event/id->i_private into call->event.type

Pull vfs fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: add missing check for __O_TMPFILE in fcntl_init()
  fs: Allow unprivileged linkat(..., AT_EMPTY_PATH) aka flink
  fs: Fix file mode for O_TMPFILE
  reiserfs: fix deadlock in umount

Adding maintainer for arch/arm/mach-keystone/
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>

Srinidhi's mail address is now bouncing and he has requested
me to delete this entry.
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kevin Hilman <khilman@linaro.org>

On muxed systems, the other vgaswitcheroo client may depend on i915 to
handle the backlight. We began switching off the backlight since

commit a261b246
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 26 19:21:47 2012 +0200

    drm/i915: disable all crtcs at suspend time

breaking backlight on discreet graphics in (some) muxed systems.

Keep the backlight on when the state is changed through vgaswitcheroo.

Note: The alternative would be to add a quirk table to achieve the same
based on system identifiers, but AFAICS it would asymptotically approach
effectively the same as this patch as more IDs are added, but with the
maintenance burden of the quirk table.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55311Tested-by: Fede <fedevx@yahoo.com>
Tested-by: Aximab <laurent.debian@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59785Tested-by: sfievet <sebastien.fievet@free.fr>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The SDVO code tries to compare the encoder's and crtc's idea of the
pixel_multiplier. Normally they have to match, but when transitioning
to DPMS off, we turn off the pipe before reading out the pipe_config,
so the pixel_multiplier in the pipe_config will be 0, whereas the
encoder will still have its pixel_multiplier set to whatever value we
were using when the display was active. This leads to a warning
from intel_modeset_check_state().

WARNING: CPU: 1 PID: 2846 at drivers/gpu/drm/i915/intel_sdvo.c:1378 intel_sdvo_get_config+0x158/0x160()
SDVO pixel multiplier mismatch, port: 0, encoder: 1
Modules linked in: snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep
CPU: 1 PID: 2846 Comm: Xorg Not tainted 3.11.0-rc3-00208-gbe1e8d7-dirty #19
Hardware name: Apple Computer, Inc. Macmini1,1/Mac-F4208EC8, BIOS  MM11.88Z.0055.B03.0604071521 04/07/06
 00000000 00000000 ef0afa54 c1597bbb c1737ea4 ef0afa84 c10392ca c1737e6c
 ef0afab0 00000b1e c1737ea4 00000562 c12dfbe8 c12dfbe8 ef0afb14 00000000
 f697ec00 ef0afa9c c103936e 00000009 ef0afa94 c1737e6c ef0afab0 ef0afadc
Call Trace:
 [<c1597bbb>] dump_stack+0x41/0x56
 [<c10392ca>] warn_slowpath_common+0x7a/0xa0
 [<c103936e>] warn_slowpath_fmt+0x2e/0x30
 [<c12dfbe8>] intel_sdvo_get_config+0x158/0x160
 [<c12c3220>] check_crtc_state+0x1e0/0xb10
 [<c12cdc7d>] intel_modeset_check_state+0x29d/0x7c0
 [<c12dfe5c>] intel_sdvo_dpms+0x5c/0xa0
 [<c12985de>] drm_mode_obj_set_property_ioctl+0x40e/0x420
 [<c1298625>] drm_mode_connector_property_set_ioctl+0x35/0x40
 [<c1289294>] drm_ioctl+0x3e4/0x540
 [<c10fc1a2>] do_vfs_ioctl+0x72/0x570
 [<c10fc72f>] SyS_ioctl+0x8f/0xa0
 [<c159b7fa>] sysenter_do_call+0x12/0x22
---[ end trace 7ce940aff1366d60 ]---

Fix the problem by skipping the encoder get_config() function for
inactive encoders.
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Some card's max brightness level is pretty large, e.g. on Acer Aspire
4732Z, the max level is 989910. If user space set a large enough level
then the current scale done in intel_panel_set_backlight will cause an
integer overflow and the scaled level will be mistakenly small, leaving
user with an almost black screen. This patch fixes this problem.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
[danvet: Add a comment to explain what's going on.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The DRM layer keeps track of our vblanks and it assumes our vblank
counters only go back to zero when they overflow. The problem is that
when we disable the power well our counters also go to zero, but it
doesn't mean they did overflow. So on this patch we grab the lock and
update last_vblank so the DRM layer won't think our counters
overflowed.

This patch fixes the following intel-gpu-tools test:
./kms_flip --run-subtest blocking-absolute-wf_vblank

Regression introduced by the following commit:

commit bf51d5e2
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Wed Jul 3 17:12:13 2013 -0300
    drm/i915: switch disable_power_well default value to 1

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66808Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Added a comment that this might be better done in
drm_vblank_post_modeset in general.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>