From commit d1a513be ("drm/i915/gvt: add resolution definition for vGPU
type"), small type has been restricted to small resolution, so not
require larger high GM size any more. Change to smaller 384M for more
VM creation with vGPU enabled which still perform reasonable workload.

Fixes: d1a513be ("drm/i915/gvt: add resolution definition for vGPU type")
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

intel_shadow_wa_ctx is a field of intel_vgpu_workload. container_of() can
be used to refine the relation-ship between intel_shadow_wa_ctx and
intel_vgpu_workload. This patch removes the useless dereference.

v2. add "drm/i915/gvt" prefix. (Zhenyu)
Signed-off-by: NTina Zhang <tina.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Turn on KBL WS platform support in gvt-g. More platforms would be
enabled, after validate.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Extend function dispatch logic to support KBL platform.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Add some KBL specially registers to save/restore list.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Update MMIO handle policy to KBL platform.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Add KBL platform definition.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

This adds initial attribute group for mdev to hold vGPU related
for each mdev device, currently just vGPU id is shown.

v2: rename group name as "intel_vgpu"
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: NKevin Tian <kevin.tian@intel.com>

GVT-g will emulate a fixed DPCD data to VM for DP/eDP panel. Update
this data to latest DP1.2 with the maximum lane bandwidth of 5.4G/s
to support 4K resolution in VM.

V3: modify patch comment
V2: add inline comment to describe the dpcd_fix_data.
Signed-off-by: NPei Zhang <pei.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Initialize the correct vreg for virtual monitor.
Set PG0/1/2 distribution and fuse download done in SKL_FUSE_STATUS.
Set PLL_ENABLE and PLL_LOCK in LCPLL_CTL.
Guest may need to check these registers for display monitor detection
on Skylake platforms.
Signed-off-by: NWeinan Li <weinan.z.li@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Backmerge drm-next one more because Dave fumbled the conflict
resolution slightly and I didn't notice it. We need Zhenyu's hotfix
before he can assemble the gvt pull ...
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

From commit 73dec95e ("drm/i915: Emit to ringbuffer directly"),
copy_gma_to_hva() now returns copied data length instead of 0, so
need to change error return check for that.

Note: Looks this is caused by backmerge conflict resolving, so
4.11-rc4 is not impacted as commit 73dec95e ("drm/i915: Emit to
ringbuffer directly") is not in 4.11. But need to fix this before I
can apply 4.12 stuff against drm-intel-next correctly.

Fixes: e5c1ff14 ("Backmerge tag 'v4.11-rc4' into drm-next")
Cc: Dave Airlie <airlied@redhat.com>
Cc: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Several major vendor USB-C->HDMI converters, in particular the DA200,
fail to recover a 5.4 GHz 1 lane signal if the link N is greater than
0x80000.

The link M and N depend on the pixel clock and link clock ratio. With
current code link N exceeds 0x80000 only when link clock >= 540000
kHz. Except for the eDP intermediate link clocks, at least the four
least significant bits are always zero. Just one bit shift right would
be enough to bring even the DP 1.4 810000 kHz link clock under 0x80000
link N. The pixel clock for modes that require a link clock >= 540000
kHz would also have several least significant bits zero. Unless the user
provides a mode with an odd pixel clock value, we can reduce the numbers
to reach the goal, with no loss in precision.

The DP spec even mentions sources making choices that "allow for static
and relatively small Mvid and Nvid values", thus reducing the link M/N
regardless of the sink in question seems justified.

Everything here is based on the work and information gathered by Clint
Taylor <clinton.a.taylor@intel.com>. This is just an iteration to reduce
the parameters regardless of lane count, link rate, or sink.

Reference: http://patchwork.freedesktop.org/patch/msgid/1490225256-11667-1-git-send-email-clinton.a.taylor@intel.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93578Tested-by: NMads <mads@ab3.no>
Tested-by: NPJ <foobar@pjmodos.net>
Tested-by: NFrançois Guerraz <kubrick@fgv6.net>
Tested-by: NLev Popov <leo@nabam.net>
Tested-by: NIgor Krivenko <igor.s.krivenko@gmail.com>
Tested-by: NClint Taylor <clinton.a.taylor@intel.com>
Reviewed-by: NClint Taylor <clinton.a.taylor@intel.com>
Reviewed-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: Clint Taylor <clinton.a.taylor@intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1490614405-23337-1-git-send-email-jani.nikula@intel.com

Capturing GPU state requires the device to be awake in order to read
registers. Normally, this is taken along the error handler, but for the
direct debugfs access, we cannot make assumptions about the current
device state and so either need to wake it up, or abort.

Fixes: 5a4c6f1b ("drm/i915: The return of i915_gpu_info to debugfs")
Testcase: igt/pm_rpm/debugfs-read
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170328131407.14863-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

We don't expect the core runtime PM get helpers to return any error, so
add a WARN for this. Also print the return value for all the callsites
to help debugging.

v2:
- Don't call pm_runtime_get_sync() as part of initing locals. (Chris)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1490693935-12638-1-git-send-email-imre.deak@intel.com

Don't throw a warning if we are given an invalid property id. While
here let's also bring back Robert' original idea of catching unhandled
enumeration values at compile time.

Fixes: eec688e1 ("drm/i915: Add i915 perf infrastructure")
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Robert Bragg <robert@sixbynine.org>
Reviewed-by: NRobert Bragg <robert@sixbynine.org>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327203236.18276-1-matthew.auld@intel.com

The old URL works but gives 301 Moved Permanently. Update.
Reviewed-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1489574966-27200-1-git-send-email-jani.nikula@intel.com

Backmerge drm-next to get at -rc4, which we need to land the 4.12 gvt
patches.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Linux 4.11-rc4

The i915 GVT team need the rc4 code to base some more code on.

If we were to ever encounter a sample_flags mismatch we need to ensure
we destroy the stream when we bail.

Fixes: d7965152 ("drm/i915: Enable i915 perf stream for Haswell OA unit")
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Robert Bragg <robert@sixbynine.org>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327203459.18398-1-matthew.auld@intel.com

Geminilake has a native HDMI 2.0 controller, which is capable of
driving clocks upto 594Mhz. This patch updates the max tmds clock
limit for the same.

V2: rebase
V3: rebase
V4: added r-b from Ander
V5: rebase
V6: rebase
V7: rebase
V8: rebase
V9: rebase
V10: rebase

Cc: Ander Conselvan De Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Reviewed-by: NAnder Conselvan De Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1489404244-16608-7-git-send-email-shashank.sharma@intel.com

Geminilake platform sports a native HDMI 2.0 controller, and is
capable of driving pixel-clocks upto 594Mhz. HDMI 2.0 spec
mendates scrambling for these higher clocks, for reduced RF footprint.

This patch checks if the monitor supports scrambling, and if required,
enables it during the modeset.

V2: Addressed review comments from Ville:
 - Do not track scrambling status in DRM layer, track somewhere in
   driver like in intel_crtc_state.
 - Don't talk to monitor at such a low layer, set monitor scrambling
   in intel_enable_ddi() before enabling the port.

V3: Addressed review comments from Jani
 - In comments, function names, use "sink" instead of "monitor",
   so that the implementation could be close to the language of
   HDMI spec.

V4: Addressed review comment from Maarten
 - scrambling -> hdmi_scrambling
 - high_tmds_clock_ratio -> hdmi_high_tmds_clock_ratio

V5: Addressed review comments from Ville and Ander
 - Do not modifiy the crtc_state after compute_config. Move all
   scrambling and tmds_clock_ratio calcutations to compute_config.
 - While setting scrambling for source/sink, do not check the
   conditions again, just go by the crtc_state flags. This will
   simplyfy the condition checks.

V6: Addressed review comments from Ville
 - Do not add IS_GLK check in disable/enable function, instead add it
   in compute_config, while setting state flags.
 - Remove unnecessary paranthesis.
 - Simplyfy handle_sink_scrambling function as suggested.
 - Add readout code for scrambling status in get_ddi_config and add a
   check for the same in pipe_config_compare.

V7: Addressed review comments from Ander/Ville
 - No separate function for source scrambling, make it inline
 - Align the last line of the macro TRANS_DDI_HDMI_SCRAMBLING_MASK
 - Do not add platform check while setting source scrambling
 - Use pipe_config instead of crtc->config to set sink scrambling
 - To readout scrambling status, Compare with SCRAMBLING_MASK
   not any of its bits
 - Remove platform check in intel_pipe_config_compare while checking
   scrambling status

V8: Fixed mege conflict, Addressed review comments from Ander
 - Remove the desciption/comment about scrambling fom the caller, move
   it to the function
 - Move the IS_GLK check into scrambling function
 - Fix alignment

V9: Fixed review comments from Ville, Ander
 - Pass the scrambling state variables as bool input to the sink_scrambling
   function and let the disable call be unconditional.
 - Fix alignments in function calls and debug messages.
 - Add kernel doc for function intel_hdmi_handle_sink_scrambling

V10: Rebase
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Reviewed-by: NAnder Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1489404244-16608-6-git-send-email-shashank.sharma@intel.com

All it does is pick the encoder and call intel_get_shared_dpll(). We
can just do this in the caller. One less indirection level during code
reading.

As another plus, now the two callers of intel_get_shared_dpll() are
{ironlake,haswell}_crtc_compute_clock().
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1490209125-20046-2-git-send-email-paulo.r.zanoni@intel.com

Use the incoming value from debugfs/i915_wedged to select which engines
to marked as guilty in order to force us to reset those requests
(required to quickly bypass simulated hangs).

Testcase: igt/gem_exec_capture
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170325134735.30581-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>

Whilst I like having the assertions clearly visible in the code, they
are quite repetitious! As we find new limits we want to incorporate into
the set of assertions, it make sense to refactor them to a common
routine.

v2: Add a guc holdout.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327131412.20293-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

In addition to being qword-aligned, the RING_TAIL offset must be within
the ring!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327130009.4678-2-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

If the request->wa_tail is 0 (because it landed exactly on the end of
the ringbuffer), when we reconstruct request->tail following a reset we
fill in an illegal value (-8 or 0x001ffff8). As a result, RING_HEAD is
never able to catch up with RING_TAIL and the GPU spins endlessly. If
the ring contains a couple of breadcrumbs, even our hangcheck is unable
to catch the busy-looping as the ACTHD and seqno continually advance.

v2: Move the wrap into a common intel_ring_wrap().

Fixes: a3aabe86 ("drm/i915/execlists: Reinitialise context image after GPU hang")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: <stable@vger.kernel.org> # v4.10+
Link: http://patchwork.freedesktop.org/patch/msgid/20170327130009.4678-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

All the pre-SKL sprite planes compute the x/y/tile offsets in a
similar way. There are a couple of minor differences but the primary
planes have those as well. Thus i9xx_check_plane_surface()
already does what we need, so let's use it.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-7-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

The effective difference between i9xx_update_primary_plane()
and ironlake_update_primary_plane() is only the HSW/BDW
DSPOFFSET special case. So bring that over into
i9xx_update_primary_plane() and eliminate the duplicated code.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-6-ville.syrjala@linux.intel.com

Extract the primary plane surfae offset/x/y calculations for
pre-SKL platforms into a common function, and call it during the
atomic check phase to reduce the amount of stuff we have to do
during the commit phase. SKL is already doing this.

v2: Update the comment about the rotation adjustments to
    match the code better (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-5-ville.syrjala@linux.intel.com

Computing the plane control register value is branchy so moving it out
from the plane commit hook seems prudent. Let's pre-compute it during
the atomic check phase and store the result in the plane state.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-4-ville.syrjala@linux.intel.com

Share the code to compute the primary plane control register value
between the i9xx and ilk codepaths as the differences are minimal.
Actually there are no differences between g4x and ilk, so the
current split doesn't really make any sense.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-3-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Pull the code to calculate the pre-SKL primary plane control register
value into separate functions. Allows us to pre-compute it in the
future.

v2: Split the pre-ilk vs. ilk+ unification to a separate patch (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323192712.30682-2-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Since the engine's flag is just the bit of its id, use BIT().
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170324163540.31981-3-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

intel_flush_status_page() is defunct since commit f8dd2934
("drm/i915: Remove BXT incoherent seqno write workaround"), time to
remove it.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170324163540.31981-2-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Not all of our target platforms have clflush. For those without, just
assume the status page is sufficiently coherent that we do not need our
paranoia.
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Fixes: 14a6bbf9 ("drm/i915: Replace irq_seqno_barrier on hws write with a clflush")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170324163540.31981-1-chris@chris-wilson.co.ukTested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

Old devices have quite severe restrictions for using fences, and unlike
more recent device (anything from Pineview onwards) we need to enforce
those restrictions even for unfenced tiled access from the render
pipeline.

Fixes: 944397f0 ("drm/i915: Store required fence size/alignment for GGTT vma")
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.11-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/20170325113243.16438-1-chris@chris-wilson.co.ukReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Tested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

We have only 8bits of precise timestamps in which to complete our
upper/load reads, along with the switch between precision. This is not
always enough time to read the upper counter twice within the same time
slice, leading to hard lockups. Limit the number of times to prevent
an inifite loop (my fault for assuming we would have no trouble doing
the write + reads fast enough).

Fixes: 47c21d9a ("drm/i915: Extend vlv/chv residency resolution")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100377Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170324165418.7455-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>

We can assume that if the device is asleep then all pending GTT writes
will have been posted, and so we can defer the flush from
i915_gem_object_flush_gtt_write_domain()

[ 1957.462568] WARNING: CPU: 0 PID: 6132 at drivers/gpu/drm/i915/intel_drv.h:1742 fwtable_read32+0x123/0x150 [i915]
[ 1957.462582] RPM wakelock ref not held during HW access
[ 1957.462583] Modules linked in: i915 intel_gtt drm_kms_helper prime_numbers
[ 1957.462607] CPU: 0 PID: 6132 Comm: gem_concurrent_ Tainted: G     U          4.11.0-rc1+ #464
[ 1957.462619] Hardware name:                  /        , BIOS PYBSWCEL.86A.0027.2015.0507.1758 05/07/2015
[ 1957.462630] Call Trace:
[ 1957.462646]  dump_stack+0x4d/0x6f
[ 1957.462657]  __warn+0xc1/0xe0
[ 1957.462667]  warn_slowpath_fmt+0x4a/0x50
[ 1957.462709]  fwtable_read32+0x123/0x150 [i915]
[ 1957.462750]  i915_gem_object_flush_gtt_write_domain+0x43/0x70 [i915]
[ 1957.462791]  i915_gem_object_set_to_cpu_domain+0x46/0xa0 [i915]
[ 1957.462831]  i915_gem_set_domain_ioctl+0x15d/0x220 [i915]
[ 1957.462843]  drm_ioctl+0x1d7/0x440
[ 1957.462885]  ? i915_gem_obj_prepare_shmem_write+0x1d0/0x1d0 [i915]
[ 1957.462896]  ? pick_next_task_fair+0x436/0x440
[ 1957.462906]  ? mntput+0x1f/0x30
[ 1957.462915]  do_vfs_ioctl+0x8f/0x5c0
[ 1957.462925]  ? __schedule+0x16f/0x5f0
[ 1957.462935]  ? ____fput+0x9/0x10
[ 1957.462943]  SyS_ioctl+0x3c/0x70
[ 1957.462952]  entry_SYSCALL_64_fastpath+0x17/0x98
[ 1957.462961] RIP: 0033:0x7fc542179ca7
[ 1957.462968] RSP: 002b:00007ffeef12ff98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 1957.462982] RAX: ffffffffffffffda RBX: 00007ffeef1301d0 RCX: 00007fc542179ca7
[ 1957.462990] RDX: 00007ffeef12ffd0 RSI: 00000000400c645f RDI: 0000000000000003
[ 1957.462999] RBP: 0000000000000003 R08: 000055f433bc7c40 R09: 000000000000002c
[ 1957.463006] R10: 0000000000000073 R11: 0000000000000246 R12: 0000000000000018
[ 1957.463015] R13: 000055f432c89d20 R14: 000055f432c87690 R15: 0000000000000000

Fixes: 3b5724d7 ("drm/i915: Wait for writes through the GTT to land before reading back")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170323150053.28582-1-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

I noticed that gcc was spilling the CSB to the stack, so rearrange the
code to be more compact. Spilling in this function is slightly more
interesting due to the mmio reads acting as memory barriers and so
end up flushing the stack spills. Still miniscule to having to do at
least the pair of uncached reads :(

function                                     old     new   delta
intel_lrc_irq_handler                       1039     878    -161
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170325201053.21306-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>