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>

Useful for checking whether the new refcounting works as advertised.
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>

Well, at least step 1. The goal here is that framebuffer objects can
survive outside of the mode_config lock, with just a reference held
as protection. The first step to get there is to introduce a special
fb_lock which protects fb lookup, creation and destruction, to make
them appear atomic.

This new fb_lock can nest within the mode_config lock. But the idea is
(once the reference counting part is completed) that we only quickly
take that fb_lock to lookup a framebuffer and grab a reference,
without any other locks involved.

vmwgfx is the only driver which does framebuffer lookups itself, also
wrap those calls to drm_mode_object_find with the new lock.

Also protect the fb_list walking in i915 and omapdrm with the new lock.

As a slight complication there's also the list of user-created fbs
attached to the file private. The problem now is that at fclose() time
we need to walk that list, eventually do a modeset call to remove the
fb from active usage (and are required to be able to take the
mode_config lock), but in the end we need to grab the new fb_lock to
remove the fb from the list. The easiest solution is to add another
mutex to protect this per-file list.

Currently that new fbs_lock nests within the modeset locks and so
appears redudant. But later patches will switch around this sequence
so that taking the modeset locks in the fb destruction path is
optional in the fastpath. Ultimately the goal is that addfb and rmfb
do not require the mode_config lock, since otherwise they have the
potential to introduce stalls in the pageflip sequence of a compositor
(if the compositor e.g. switches to a fullscreen client or if it
enables a plane). But that requires a few more steps and hoops to jump
through.

Note that framebuffer creation/destruction is now double-protected -
once by the fb_lock and in parts by the idr_lock. The later would be
unnecessariy if framebuffers would have their own idr allocator. But
that's material for another patch (series).

v2: Properly initialize the fb->filp_head list in _init, otherwise the
newly added WARN to check whether the fb isn't on a fpriv list any
more will fail for driver-private objects.

v3: Fixup two error-case unlock bugs spotted by Richard Wilbur.
Reviewed-by: NRob Clark <rob@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Two exceptions:
- debugfs files only read information which is not related to crtc, so
  can stay on the modeset_config lock.
- Same holds for the edp vdd work in intel_dp.c. Add a corresponding
  WARN_ON and a comment next to the intel_dp struct fields for
  documentation.
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 partially reverts

commit 6c085a72
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Aug 20 11:40:46 2012 +0200

    drm/i915: Track unbound pages

Closer inspection of that patch revealed a bunch of unrelated changes
in the shrinker:
- The shrinker count is now in pages instead of objects.
- For counting the shrinkable objects the old code only looked at the
  inactive list, the new code looks at all bounds objects (including
  pinned ones). That is obviously in addition to the new unbound list.
- The shrinker cound is no longer scaled with
  sysctl_vfs_cache_pressure. Note though that with the default tuning
  value of vfs_cache_pressue = 100 this doesn't affect the shrinker
  behaviour.
- When actually shrinking objects, the old code first dropped
  purgeable objects, then normal (inactive) objects. Only then did it,
  in a last-ditch effort idle the gpu and evict everything. The new
  code omits the intermediate step of evicting normal inactive
  objects.

Safe for the first change, which seems benign, and the shrinker count
scaling, which is a bit a different story, the endresult of all these
changes is that the shrinker is _much_ more likely to fall back to the
last-ditch resort of idling the gpu and evicting everything.  The old
code could only do that if something else evicted lots of objects
meanwhile (since without any other changes the nr_to_scan will be
smaller than the object count).

Reverting the vfs_cache_pressure behaviour itself is a bit bogus: Only
dentry/inode object caches should scale their shrinker counts with
vfs_cache_pressure. Originally I've had that change reverted, too. But
Chris Wilson insisted that it's too bogus and shouldn't again see the
light of day.

Hence revert all these other changes and restore the old shrinker
behaviour, with the minor adjustment that we now first scan the
unbound list, then the inactive list for each object category
(purgeable or normal).

A similar patch has been tested by a few people affected by the gen4/5
hangs which started to appear in 3.7, which some people bisected to
the "drm/i915: Track unbound pages" commit. But just disabling the
unbound logic alone didn't change things at all.

Note that this patch doesn't fix the referenced bugs, it only hides
the underlying bug(s) well enough to restore pre-3.7 behaviour. The
key to achieve that is to massively reduce the likelyhood of going
into a full gpu stall and evicting everything.

v2: Reword commit message a bit, taking Chris Wilson's comment into
account.

v3: On Chris Wilson's insistency, do not reinstate the rather bogus
vfs_cache_pressure change.
Tested-by: NGreg KH <gregkh@linuxfoundation.org>
Tested-by: NDave Kleikamp <dave.kleikamp@oracle.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=55984
References: https://bugs.freedesktop.org/show_bug.cgi?id=57122
References: https://bugs.freedesktop.org/show_bug.cgi?id=56916
References: https://bugs.freedesktop.org/show_bug.cgi?id=57136
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This fixes an original bug in the sprite code that miscomputed the
source offset into a linear YUV packed framebuffer, that was magnified
into an oops with

commit 5a35e99e
Author: Damien Lespiau <damien.lespiau@intel.com>
Date:   Fri Oct 26 18:20:12 2012 +0100

    drm/i915: adjust sprite base address
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
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>

Increasing ref counts of both dma-buf and gem for imported dma-buf come from gem
makes memory leak. release function of dma-buf cannot be called because f_count
of dma-buf increased by importing gem and gem ref count cannot be decrease
because of exported dma-buf.

So I add dma_buf_put() for imported gem come from its own gem into each drivers
having prime_import and prime_export capabilities. With this, only gem ref
count is increased if importing gem exported from gem of same driver.
Signed-off-by: NSeung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: NKyungmin.park <kyungmin.park@samsung.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <rob.clark@linaro.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Prevent a divide-by-zero by consistently treating an 'active' CRTC
without a mode set as actually disabled.

This looks to have been first introduced with

commit 24929352
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Jul 2 20:28:59 2012 +0200

    drm/i915: read out the modeset hw state at load and resume time

but then combined with

commit b0a2658a
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Dec 18 09:37:54 2012 +0100

    drm/i915: don't disable disconnected outputs

it finally started oopsing.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: NAlexey Zaytsev <alexey.zaytsev@gmail.com>
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 9756fe38.

The bogus lvds output is actually a lvds->hdmi bridge, which we don't
really support. But unconditionally disabling it breaks some existing
setups.
Reported-by: NJohn Tapsell <johnflux@gmail.com>
References: http://permalink.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/17237Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As along the error path we do not correct the user pin-count for the
failure, we may end up with userspace believing that it has a pinned
object at offset 0 (when interrupted by a signal for example).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, and __devexit
from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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>

The iomapping of the register region has historically been a uint32_t
for the obvious reason that our PTE size was always 4b. In the future
however, we cannot make this assumption.

By making the type void, it makes the upcoming pointer math we will do
much easier, and hopefully gives the compiler opportunities to warn us
when we do stupid things.

v2: Cast to __iomem, caught by Ville
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Fixup __iomem issue for real.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This removes an unused field from the AGP structure and moves it into
the dev_priv structure (with a slightly better name). This builds upon
the kill-agp series already merged.

GSM is a well defined term in the bspec:
GSM: Graphics Stolen Memory

GTT stolen space is defined for storage of the GFX GTT entries in
physical memory. IA can not access GSM directly , it can only access via
GTTMMADR. GT can access GSM directly or through GTTMMADR.

This is not the entire stolen space.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This really should have been part of the kill agp series.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The mmap offset structure is not part of the drm/i915 code, but
provided by gem helpers. To avoid leaky abstractions (by either
depending upon implementation details of said helper wrt to
preallocations, or reimplementing it in our code and so fuzzing
around in internal details of that helpr) simply disable
the shrinker lock stealing accross calls into the helper functions.

This should fix igt/gem_tiled_swapping.

v2: Fix cleanup path confusion bemoaned by Chris Wilson.
Reported-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit 5774506f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Nov 21 13:04:04 2012 +0000

    drm/i915: Borrow our struct_mutex for the direct reclaim

added a nice trick to steal the struct_mutex lock in the shrinker if
it's the current task holding it. But this also caused the requirement
that every place which allocates memory needs to be careful about the
gem state of objects, since the shrinker could have pulled the rug out
from under it. We've usually solved this by carefully preallocating
things or ensure that buffers are pinned already.

But the shrinker also reaps mmap offset, so allocating those needs to
be careful, too. Now that code has been factored out into some common
helpers, so either we have fragile code depending upon the common
helper not doing something we don't want it to do. Or we need to
reimplement the mmap offset creation and so also leak implementation
details into our code.

Since this all results in leaky abstraction, cop out by disabling the
lock borrowing trick while calling down into the helpers. That way our
craziness is nicely confined to files in drm/i915.

v2: Split out the change to create_mmap_offset as request by Chris Wilson.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As pointed out by Seung-Woo Kim this should have been
passing flags like nouveau/radeon have.

Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>
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 debugs entry can be used to set arbitrary value to next_seqno.
Use i915_gem_set_seqno instead of poking next_seqno.

v2: nasty details of next_seqno and last_seqno handling
moved inside i915_gem_set_seqno as suggested by Chris Wilson.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This function can be used to set the driver's next_seqno
to arbitrary value.

i915_gem_set_seqno() will idle the gpu, retire outstanding
requests, clear the semaphore mailboxes and set the hardware
status page's seqno index.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In preparation for setting the seqno to arbitrary value on init or
through debugfs. We need to always clear the semaphores and set the
hws page seqno index by calling intel_ring_init_seqno().

v2: rewrote the commit message as suggested by Chris Wilson.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Hardware status page needs to have proper seqno set
as our initial seqno can be arbitrary. If initial seqno is close
to wrap boundary on init and i915_seqno_passed() (31bit space)
refers to hw status page which contains zero, errorneous result
will be returned.

v2: clear mboxes and set hws page directly instead of going
through rings. Suggested by Chris Wilson.

v3: hws needs to be updated for all gens. Noticed by Chris
Wilson.

References: https://bugs.freedesktop.org/show_bug.cgi?id=58230Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In preparation for setting per ring initial seqno values
add ring::set_seqno().
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit f61c0609
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Mon Oct 22 11:44:43 2012 -0700

    drm/i915: introduce gtt_pte_t
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As we may reap neighbouring objects in order to free up pages for
allocations, we need to be careful not to allocate in the middle of the
drm_mm manager. To accomplish this, we can simply allocate the
drm_mm_node up front and then use the combined search & insert
drm_mm routines, reducing our code footprint in the process.

Fixes (partially) i-g-t/gem_tiled_swapping
Reported-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Again fixup atomic bikeshed.]
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>

Now that Chris Wilson demonstrated that the key for stability on early
gen 2 is to simple _never_ exchange the physical backing storage of
batch buffers I've tried a stab at a kernel solution. Doesn't look too
nefarious imho, now that I don't try to be too clever for my own good
any more.

v2: After discussing the various techniques, we've decided to always blit
batches on the suspect devices, but allow userspace to opt out of the
kernel workaround assume full responsibility for providing coherent
batches. The principal reason is that avoiding the blit does improve
performance in a few key microbenchmarks and also in cairo-trace
replays.
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet:
- Drop the hunk which uses HAS_BROKEN_CS_TLB to implement the ring
  wrap w/a. Suggested by Chris Wilson.
- Also add the ACTHD check from Chris Wilson for the error state
  dumping, so that we still catch batches when userspace opts out of
  the w/a.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

I'm not really sure, since the w/a entry is as thin on details as
ever, and Bspec doesn't say anything about it. But I've figured only
dispatching to rows 0&1 instead of all four should be the right thing
for GT1.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Add the missing snb server GT1 to the check, spotted by Chris
Wilson.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Quoting from Bspec, 3D_CHICKEN1, bit 10

This bit needs to be set always to "1", Project: DevSNB "
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
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>

So we can de-duplicate code that's inside intel_dp_start_link_train
and intel_dp_complete_link_train.

V2: Rebase since patch 3/5 was discarded.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>