One of the early return cases missed the mutex unlocking. Hilarity
ensued.

This regression has been introduced in

commit 7b24056b
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Dec 12 00:35:33 2012 +0100

    drm: don't hold crtc mutexes for connector ->detect callbacks

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59750Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: NCancan Feng <cancan.feng@intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

The coup de grace of the entire journey. No more dropped frames every
10s on my testbox!

I've tried to audit all ->detect and ->get_modes callbacks, but things
became a bit fuzzy after trying to piece together the umpteenth
implemenation. Afaict most drivers just have bog-standard output
register frobbing with a notch of i2c edid reading, nothing which
could potentially race with the newly concurrent pageflip/set_cursor
code. The big exception is load-detection code which requires a
running pipe, but radeon/nouveau seem to to this without touching any
state which can be observed from page_flip (e.g. disabled crtcs
temporarily getting enabled and so a pageflip succeeding).

The only special case I could find is the i915 load detect code. That
uses the normal modeset interface to enable the load-detect crtc, and
so userspace could try to squeeze in a pageflip on the load-detect
pipe. So we need to grab the relevant crtc mutex in there, to avoid
the temporary crtc enabling to sneak out and be visible to userspace.

Note that the sysfs files already stopped grabbing the per-crtc locks,
since I didn't want to bother with doing a interruptible
modeset_lock_all. But since there's very little in-between breakage
(essentially just the ability for userspace to pageflip on load-detect
crtcs when it shouldn't on the i915 driver) I figured I don't need to
bother.
Reviewed-by: NRob Clark <rob@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have two classes of framebuffer
- Created by the driver (atm only for fbdev), and the driver holds
  onto the last reference count until destruction.
- Created by userspace and associated with a given fd. These
  framebuffers will be reaped when their assoiciated fb is closed.

Now these two cases are set up differently, the framebuffers are on
different lists and hence destruction needs to clean up different
things. Also, for userspace framebuffers we remove them from any
current usage, whereas for internal framebuffers it is assumed that
the driver has done this already.

Long story short, we need two different ways to cleanup such drivers.
Three functions are involved in total:
- drm_framebuffer_remove: Convenience function which removes the fb
  from all active usage and then drops the passed-in reference.
- drm_framebuffer_unregister_private: Will remove driver-private
  framebuffers from relevant lists and drop the corresponding
  references. Should be called for driver-private framebuffers before
  dropping the last reference (or like for a lot of the drivers where
  the fbdev is embedded someplace else, before doing the cleanup
  manually).
- drm_framebuffer_cleanup: Final cleanup for both classes of fbs,
  should be called by the driver's ->destroy callback once the last
  reference is gone.

This patch just rolls out the new interfaces and updates all drivers
(by adding calls to drm_framebuffer_unregister_private at all the
right places)- no functional changes yet. Follow-on patches will move
drm core code around and update the lifetime management for
framebuffers, so that we are no longer required to keep framebuffers
alive by locking mode_config.mutex.

I've also updated the kerneldoc already.

vmwgfx seems to again be a bit special, at least I haven't figured out
how the fbdev support in that driver works. It smells like it's
external though.

v2: The i915 driver creates another private framebuffer in the
load-detect code. Adjust its cleanup code, too.
Reviewed-by: NRob Clark <rob@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With more fine-grained locking we can no longer rely on the big
mode_config lock to prevent concurrent access to mode resources
like framebuffers. Instead a framebuffer becomes accessible to
other threads as soon as it is added to the relevant lookup
structures. Hence it needs to be fully set up by the time drivers
call drm_framebuffer_init.

This patch here is the drivers part of that reorg. Nothing really fancy
going on safe for three special cases.

- exynos needs to be careful to properly unref all handles.
- nouveau gets a resource leak fixed for free: one of the error
  cases didn't cleanup the framebuffer, which is now moot since
  the framebuffer is only registered once it is fully set up.
- vmwgfx requires a slight reordering of operations, I'm hoping I didn't
  break anything (but it's refcount management only, so should be safe).

v2: Split out exynos, since it's a bit more hairy than expected.

v3: Drop bogus cirrus hunk noticed by Richard Wilbur.

v4: Split out vmwgfx since there's a small change in return values.

Reviewed-by: Rob Clark <rob@ti.com> (core + omapdrm)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This proves to be very useful when investigating why code suddenly
started failing.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This fixes a regression from

commit 57779d06
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Wed Oct 31 17:50:14 2012 +0200

    drm/i915: Fix display pixel format handling

(which even says that they are supported on Ironlake, and then promptly
rejects then...)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Note: This patch also adds a little helper intel_crtc_restore_mode for
the common case where we do a full modeset but with the same
parameters, e.g. to undo bios damage or update a property.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Added note.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some broken systems (like HP nc6120) in some cases, usually after LID
close/open, enable VGA plane, making display unusable (black screen on LVDS,
some strange mode on VGA output). We used to disable VGA plane only once at
startup. Now we also check, if VGA plane is still disabled while changing
mode, and fix that if something changed it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=57434Signed-off-by: NKrzysztof Mazur <krzysiek@podlesie.net>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This piece of neat lore has been ported painstakingly and bug-for-bug
compatible from the old crtc helper code.

Imo it's utter nonsense.

If you disconnected a cable and before you reconnect it, userspace (or
the kernel) does an set_crtc call, this will result in that connector
getting disabled. Which will result in a nice black screen when
plugging in the cable again.

There's absolutely no reason the kernel does such policy enforcements
- if userspace tries to set up a mode on something disconnected we
might fail loudly (since the dp link training fails), but silently
adjusting the output configuration behind userspace's back is a recipe
for disaster. Specifically I think that this could explain some of our
MI_WAIT hangs around suspend, where userspace issues a scanline wait
on a disable pipe. This mechanisims here could explain how that pipe
got disabled without userspace noticing.

Note that this fixes a NULL deref at BIOS takeover when the firmware
sets up a disconnected output in a clone configuration with a
connected output on the 2nd pipe: When doing the full modeset we don't
have a mode for the 2nd pipe and OOPS. On the first pipe this doesn't
matter, since at boot-up the fbdev helpers will set up the choosen
configuration on that on first. Since this is now the umptenth bug
around handling this imo brain-dead semantics correctly, I think it's
time to kill it and see whether there's any userspace out there which
relies on this.

It also nicely demonstrates that we have a tiny window where DP
hotplug can still kill the driver.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=58396
Cc: stable@vger.kernel.org
Tested-by: NPeter Ujfalusi <peter.ujfalusi@gmail.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to clean up the overlay first, before taking down the
stolen memory allocator.

This regression has been introducec in

commit 80405138
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 15 11:32:29 2012 +0000

    drm/i915: Allocate overlay registers from stolen memory

v2: Rework the patch a bit as suggested by Chris Wilson:
- move the overlay teardown up, into the modeset cleanup
- move the stolen mm takedown into i915_gem_cleanup_stolen

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ilk+ somehow used #defines in near the PIPESTAT definitions, which
decently confused me. Earlier platforms called it BPP instead of
BPC. Clean this all up.
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was moved to intel_init_pm.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Don't check the CPU, it doesn't have any PCH transcoder.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

CPT+ PCHs have different bit definition to read the HPD live status. I
don't have an ILK with digital ports handy, which is why this patch is
separate from the CPT+ implementation. If the docs don't lie, it should
all be fine though.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If you unplug the hdmi connector slowly enough, the hotplug interrupt
fires but then the kernel code tries to read the EDID and succeeds
(because the connector is still half connected, the HPD pin is shorter
than the others, and DDC works). Since EDID succeeds it thinks the
monitor is still connected.

To prevent that, read the live HPD status in the hotplug handler before
trying to read the EDID.

v2: Rename the function to ibx_ (Chris Wilson)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55372Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Spinning for up to 200 us with interrupts locked out is not good. So
let's just spin (and even that seems to be excessive).

And we don't call these functions from interrupt context, so this is
not required. Besides that doing anything in interrupt contexts which
might take a few hundred us is a no-go. So just convert the entire
thing to a mutex. Also move the mutex-grabbing out of the read/write
functions (add a WARN_ON(!is_locked)) instead) since all callers are
nicely grouped together.

Finally the real motivation for this change: Dont grab the modeset
mutex in the dpio debugfs file, we don't need that consistency. And
correctness of the dpio interface is ensured with the dpio_lock.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We've originally added this in

commit 291427f5
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Jul 29 12:42:37 2011 -0700

    drm/i915: apply phase pointer override on SNB+ too

and then copy-pasted it over to ivb/ppt. The w/a was originally added
for ilk/ibx in

commit 5b2adf89
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Oct 7 16:01:15 2010 -0700

    drm/i915: add Ironlake clock gating workaround for FDI link training

and fixed up a bit in

commit 6f06ce18
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Tue Jan 4 15:09:38 2011 -0800

    drm/i915: set phase sync pointer override enable before setting phase sync pointer

It turns out that this w/a isn't actually required on cpt/ppt and
positively harmful on ivb/ppt when using fdi B/C links - it results in
a black screen occasionally, with seemingfully everything working as
it should. The only failure indication I've found in the hw is that
eventually (but not right after the modeset completes) a pipe underrun
is signalled.

Big thanks to Arthur Runyan for all the ideas for registers to check
and changes to test, otherwise I couldn't ever have tracked this down!

Cc: "Runyan, Arthur J" <arthur.j.runyan@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need this code to init the PCH SSC refclk and the FDI registers.
The BIOS does this too and that's why VGA worked before this patch,
until you tried to suspend the machine...

This patch implements the "Sequence to enable CLKOUT_DP for FDI usage
and configure PCH FDI/IO" from our documentation.

v2:
- Squash Damien Lespiau's reset spelling fix on top.
- Add a comment that we don't need to bother about the ULT special
  case Damien noticed, since ULT won't have VGA.
- Add a comment to rip out the SDV codepaths once haswell ships for
  real.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This way we should be able to write mPHY registers using the Sideband
Interface in the next commit. Also fixed some syntax oddities in the
related code.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

smatch warning:

drivers/gpu/drm/i915/intel_display.c:7019 intel_set_mode() warn: function puts
500 bytes on stack

Refactor so that saved_mode and saved_hwmode are dynamically allocated as opposed
to being automatic variables. 500 bytes seems like it could run the potential for blowing
the kernel stack.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

More specifically, the LPT FDI RX only supports 8bpc and a maximum of
2 lanes, so anything above that won't work and should be rejected.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Both the dp and fdi code use the exact same computations (ignore minor
differences in conversion between bits and bytes).

This makes it even more apparent that we have a _massive_ mess between
cpu transcoder/fdi link/pch transcoder and pch link settings. And also
that we have hilarious amounts of confusion between edp and dp
(despite that they're identical at a link level).
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This has originally been added in

commit 8db9d77b
Author: Zhenyu Wang <zhenyuw@linux.intel.com>
Date:   Wed Apr 7 16:15:54 2010 +0800

    drm/i915: Support for Cougarpoint PCH display pipeline

probably to combat issues with hw state left behind by the BIOS. And
indeed, I've checked out that specific revision, and there is no DP
support yet. So the pch dp transcoder won't be correctly disabled, and
that's important since it requires a rether special disable dance:
Just writing 0 to TRANS_DP_CTL won't cut it, since we need to select
the NONE port when disabling, too.

And indeed, things seem to still work, so let's just remove this.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we enable the cpu edp pll in intel_dp->pre_enable and no
longer in crtc_mode_set, we can also move the modeset part to the
intel_dp->mode_set callback. Previously this was not possible because
the encoder ->mode_set callbacks are called after the crtc mode set
callback.

v2: Rebase on top of copy&pasted hsw crtc_mode_set.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Especially getting rid of all things lvds is ... great!

v2: Drop the two additional pre-hsw hunks noticed by Paulo Zanoni.

v3:
- handle DP ports correctly (spoted by Paulo)
- don't leave {} behind for a single-line block (again spotted by
  Paulo)
- kill another if (IBX || CPT) block
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Before queuing the flip but crucially after attaching the unpin-work to
the crtc, we continue to setup the unpin-work. However, should the
hardware fire early, we see the connected unpin-work and queue the task.
The task then promptly runs and unpins the fb before we finish taking
the required references or even pinning it... Havoc.

To close the race, we use the flip-pending atomic to indicate when the
flip is finally setup and enqueued. So during the flip-done processing,
we can check more accurately whether the flip was expected.

v2: Add the appropriate mb() to ensure that the writes to the page-flip
worker are complete prior to marking it active and emitting the MI_FLIP.
On the read side, the mb should be enforced by the spinlocks.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
[danvet: Review the barriers a bit, we need a write barrier both
before and after updating ->pending. Similarly we need a read barrier
in the interrupt handler both before and after reading ->pending. With
well-ordered irqs only one barrier in each place should be required,
but since this patch explicitly sets out to combat spurious interrupts
with is staged activation of the unpin work we need to go full-bore on
the barriers, too. Discussed with Chris Wilson on irc and changes
acked by him.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

- __iomem where there is none (I love how we mix these things up).
- Use gfp_t instead of an other plain type.
- Unconfuse one place about enum pipe vs enum transcoder - for the pch
  transcoder we actually use the pipe enum. Fixup the other cases
  where we assign the pipe to the cpu transcoder with explicit casts.
- Declare the mch_lock properly in a header.

There is still a decent mess in intel_bios.c about __iomem, but heck,
this is x86 and we're allowed to do that.

Makes-sparse-happy: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Use a space after the cast consistently and fix up the
newly-added cast in i915_irq.c to properly use __iomem.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As FBC is commonly disabled due to limitations of the chipset upon
output configurations, on many systems FBC is never enabled. For those
systems, it is advantageous to make use of the stolen memory for other
objects and so we defer allocation of the FBC chunk until we actually
require it. This increases the likelihood of that allocation failing,
but that in turns means that we are already taking advantage of the
stolen memory!

As well as delaying the allocation from driver initialisation until the
first use of FBC, we also return the stolen block after we finish using
it - allowing greater flexibility in our usage of stolen space. A side
effect of this is that we can then attempt to allocate only the required
amount of space (with a little slack to reduce reallocation rate and
avoid fragmentation).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And use it whenever we call code that uses the DDIs. We already have
intel_ddi.c and prefix every function with intel_ddi_something instead of
haswell_something, so I think replacing the checks with HAS_DDI makes more
sense. Just a cosmetical change, yes I know, but I have this OCD...
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This function is not called on Haswell anymore.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Only two things needed adjustment:
- pipe select for PCH_CPT
- There's no dithering bit on ilk+ in the lvds ctl reg
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A few things needed to change:
- HAS_PCH_SPLIT since ilk+ is not yet converted to this.
- s/LVDS/intel_lvds->reg/ to prep for ilk conversion
- replace the clock.p2 == 7 check with a is_dual_link check
- s/adjusted_mode/intel_lvds->fixed_mode

v2: Rebase on top of Jani Nikula's panel rework. I'm wondering whether
we shouldn't add an attached_panel pointer to intel_encoder, to
replace the encoder private ->attached_connector pointers, since
that's essentially what we need.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just a prep patch to make this a property of intel_lvds. Makes more
sense, removes clutter from intel_display.c and eventually I want to
move all the encoder special cases wrt clock handling to encoders
anyway.

v2: Add an intel_ prefixe to is_dual_link_lvds since it's non-static
now.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

... with is_dual_link_lvds introduced in

commit b0354385
Author: Takashi Iwai <tiwai@suse.de>
Date:   Tue Mar 20 13:07:05 2012 +0100

    drm/i915: Check VBIOS value for determining LVDS dual channel mode, too

All these checks predate this commit and have simply been overlooked.
Since we don't support switching between single-link and dual-link
modes anyway, this different checks could at best only get in the way
of refactorings, and in the worst case cause inconsistencies.

v2: Update the comment, we now have a solid way to figure out whether
we need dual-link lvds or not (falling back to vbt values as a last
resort). We still don't know how to switch between dual-link and
single link so leave that part intact. I'm not sure though whether
switching between these two modes makes any sense - we always drive
the panel at its fixed mode (with a fixed bpc) anyway ...
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently we have two encoder specific bits in the common mode_set
functions:
- lvds pin pair enabling
- dp m/n setting and computation

Now the lvds stuff needs to happen before the pll is enabled. Since
that is done in the crtc_mode_set functions, we need to add a new
callback to be able to move them to the encoder code (where they
belong). The dp m/n stuff is a giant mess anyway (since it also
confuses itself with the fdi link m/n handling), so that needs to be
handled separately.

I think that we can move the pll enabling down quite a bit, which
might allow us to eventually merge encoder->pre_enable with this new
pre_pll_enable callback. But for now this will allow us to clean
things up a bit.

Note that vlv doesn't support lvds, hence we don't need to change
anything in there.

v2: Fixup commit message, both suggested from Paulo Zanoni.
- dp m/n doesn't need to happen before pll enabling
- lvds doesn't exist on vlv, hence no changes required in the vlv pll
  function.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As per Chris Wilson's suggestion make
i915_gem_execbuffer_wait_for_flips() go away.

This was used to stall the GPU ring while there are pending
page flips involving the relevant BO. Ie. while the BO is still
being scanned out by the display controller.

The recommended alternative is to use the page flip events to
wait for the page flips to fully complete before reusing the BO
of the old front buffer. Or use more buffers.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NKristian Høgsberg <krh@bitplanet.net>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: don't remove obj->pending_flips, still required due to
reorder patches.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There seem to be indeed some awkwards machines around, mostly those
without OpRegion support, where the firmware changes the display hw
state behind our backs when closing the lid.

This force-restore logic has been originally introduced in

commit c1c7af60
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Sep 10 15:28:03 2009 -0700

    drm/i915: force mode set at lid open time

but after the modeset-rework we've disabled it in the vain hope that
it's no longer required:

commit 3b7a89fc
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Sep 17 22:27:21 2012 +0200

    drm/i915: fix OOPS in lid_notify

Alas, no.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54677
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=57434Tested-by: NKrzysztof Mazur <krzysiek@podlesie.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit 500a8cc4
Author: Zhenyu Wang <zhenyuw@linux.intel.com>
Date:   Wed Jan 13 11:19:52 2010 +0800

    drm/i915: parse eDP panel color depth from VBT block

originally introduced parsing bpp for eDP from VBT, with a default of 18
bpp if the eDP BIOS data block is not present. Turns out that default seems
to break the Macbook Pro with retina display, as noted in

commit 4344b813
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Aug 10 11:10:20 2012 +0200

    drm/i915: ignore eDP bpc settings from vbt

Since we can't ignore bpc settings from VBT completely after all, get rid
of the default. Do not clamp eDP to 18 bpp by default if the eDP BDB is
missing from VBT.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Tested-by: NHenrik Rydberg <rydberg@euromail.se>
[danvet: paste in the updated commit message from irc.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Rebased.
Signed-off-by: NRob Clark <rob@ti.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com> (v1)
[danvet: Pimp commit message a bit.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NRob Clark <rob@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>