On KBL, WHL RVPs, booting up with an external display connected, triggers
below warning, when the BiOS brings up the external display too.
This warning is not seen during hotplug.

[    3.615226] ------------[ cut here ]------------
[    3.619829] plane 1A assertion failure (expected on, current off)
[    3.632039] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
[    3.633920] iwlwifi 0000:00:14.3: loaded firmware version 38.c0e03d94.0 op_mode iwlmvm
[    3.647157] Modules linked in: iwlwifi cfg80211 btusb btrtl btbcm btintel bluetooth ecdh_generic
[    3.647163] CPU: 2 PID: 354 Comm: frecon Not tainted 4.17.0-rc7-50176-g655af12d39c2 #3
[    3.647165] Hardware name: Intel Corporation CoffeeLake Client Platform/WhiskeyLake U DDR4 ERB, BIOS CNLSFWR1.R00.X140.B00.1804040304 04/04/2018
[    3.684509] RIP: 0010:assert_plane+0x71/0xbb
[    3.764451] Call Trace:
[    3.766888]  intel_atomic_commit_tail+0xa97/0xb77
[    3.771569]  intel_atomic_commit+0x26a/0x279
[    3.771572]  drm_atomic_helper_set_config+0x5c/0x76
[    3.780670]  __drm_mode_set_config_internal+0x66/0x109
[    3.780672]  drm_mode_setcrtc+0x4c9/0x5cc
[    3.780674]  ? drm_mode_getcrtc+0x162/0x162
[    3.789774]  ? drm_mode_getcrtc+0x162/0x162
[    3.798108]  drm_ioctl_kernel+0x8d/0xe4
[    3.801926]  drm_ioctl+0x27d/0x368
[    3.805311]  ? drm_mode_getcrtc+0x162/0x162
[    3.805314]  ? selinux_file_ioctl+0x14e/0x199
[    3.805317]  vfs_ioctl+0x21/0x2f
[    3.813812]  do_vfs_ioctl+0x491/0x4b4
[    3.813813]  ? security_file_ioctl+0x37/0x4b
[    3.813816]  ksys_ioctl+0x55/0x75
[    3.820672]  __x64_sys_ioctl+0x1a/0x1e
[    3.820674]  do_syscall_64+0x51/0x5f
[    3.820678]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[    3.828221] RIP: 0033:0x7b5e04953967
[    3.835504] RSP: 002b:00007fff2eafb6f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[    3.835505] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007b5e04953967
[    3.835505] RDX: 00007fff2eafb730 RSI: 00000000c06864a2 RDI: 000000000000000f
[    3.835506] RBP: 00007fff2eafb720 R08: 0000000000000000 R09: 0000000000000000
[    3.835507] R10: 0000000000000070 R11: 0000000000000246 R12: 000000000000000f
[    3.879988] R13: 000056bc9dd7d210 R14: 00007fff2eafb730 R15: 00000000c06864a2
[    3.887081] Code: 48 c7 c7 06 71 a5 be 84 c0 48 c7 c2 06 fd a3 be 48 89 f9 48 0f 44 ca 84 db 48 0f 45 d7 48 c7 c7 df d3 a4 be 31 c0 e8 af a0 c0 ff <0f> 0b eb 2b 48 c7 c7 06 fd a3 be 84 c0 48 c7 c2 06 71 a5 be 48
[    3.905845] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
[    3.920964] ---[ end trace dac692f4ac46391a ]---

The warning is seen when mode_setcrtc() is called for pipeB
during bootup and before we get a mode_setcrtc() for pipeA,
while doing update_crtcs() in intel_atomic_commit_tail().
Now since, plane1A is still active after commit, update_crtcs()
is done for pipeA and eventually update_plane() for plane1A.

intel_plane_state->ctl for plane1A is not updated since set_modecrtc() is
called for pipeB. So intel_plane_state->ctl for plane 1A will be 0x0.
So doing an update_plane() for plane1A, will result in clearing
PLANE_CTL_ENABLE bit, and hence the warning.

To fix this warning, force all active planes to recompute their states
in probe.

Changes in v8:
- Actually add Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Changes in v7:
- Move call to intel_initial_commit() after sanitize_watermarks()
  Otherwise the plane update will still consult potentially bogus
  watermarks we read out from the hardware. (Ville)
- Carry Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
  from v6

Changes in v6:
- Handle EDEADLK for drm_atomic_get_crtc_state() and
  drm_atomic_add_affected_planes()
- Remove optimization of calling intel_initial_commit()
  only when there is more than one active pipe in probe.
- Avoid using intel_ types.

Changes in v5:
- Drop drm_modeset_lock_all_ctx() since locks will be taken later.

Changes in v4:
- Handle locking in intel_initial_commit()
- Move the for loop inside intel_initial_commit() so that
  drm_atomic_commit() is called only once
- Call intel_initial_commit() only for more than one active crtc on boot.
- Save the return value of intel_initial_commit() and print a message in
  case of an error

Changes in v3:
- Add comments

Changes in v2:
- Force all planes to recompute their states.(Ville Syrjälä)
- Update the commit message

Signed-off-by: Azhar Shaikh <azhar.shaikh@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1530902250-44583-1-git-send-email-azhar.shaikh@intel.com

We believe we have all the kinks worked out, even for the early
Valleyview devices, for whom we currently disable all ppgtt.

References: 62942ed7

 ("drm/i915/vlv: disable PPGTT on early revs v3")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717095751.1034-2-chris@chris-wilson.co.uk

We should we have all the kinks worked out and full-ppgtt now works
reliably on gen7 (Ivybridge, Valleyview/Baytrail and Haswell). If we can
let userspace have full control over their own ppgtt, it makes softpinning
far more effective, in turn making GPU dispatch far more efficient by
virtue of better mm segregation.  On the other hand, switching over to a
different GTT for every client does incur noticeable overhead, but only
for very lightweight tasks.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jason Ekstrand <jason.ekstrand@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717095751.1034-1-chris@chris-wilson.co.uk

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

With neither LVDS or eDP no longer using intel_panel_detect() we can
kill it, and the accompanying modparam.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717174216.22252-3-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

We never registered any kind of lid notifier for eDP, so looking at the
lid status is pretty much bonkers. Let's just consider eDP always
connected instead.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717174216.22252-2-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

We broke the LVDS notifier resume thing in (presumably) commit
e2c8b870 ("drm/i915: Use atomic helpers for suspend, v2.") as
we no longer duplicate the current state in the LVDS notifier and
thus we never resume it properly either.

Instead of trying to fix it again let's just kill off the lid
notifier entirely. None of the machines tested thus far have
apparently needed it. Originally the lid notifier was added to
work around cases where the VBIOS was clobbering some of the
hardware state behind the driver's back, mostly on Thinkpads.
We now have a few report of Thinkpads working just fine without
the notifier. So maybe it was misdiagnosed originally, or
something else has changed (ACPI video stuff perhaps?).

If we do end up finding a machine where the VBIOS is still causing
problems I would suggest that we first try setting various bits in
the VBIOS scratch registers. There are several to choose from that
may instruct the VBIOS to steer clear.

With the notifier gone we'll also stop looking at the panel status
in ->detect().

v2: Nuke enum modeset_restore (Rodrigo)

Cc: stable@vger.kernel.org
Cc: Wolfgang Draxinger <wdraxinger.maillist@draxit.de>
Cc: Vito Caputo <vcaputo@pengaru.com>
Cc: kitsunyan <kitsunyan@airmail.cc>
Cc: Joonas Saarinen <jza@saunalahti.fi>
Tested-by: Vito Caputo <vcaputo@pengaru.com> # Thinkapd X61s
Tested-by: kitsunyan <kitsunyan@airmail.cc> # ThinkPad X200
Tested-by: Joonas Saarinen <jza@saunalahti.fi> # Fujitsu Siemens U9210
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105902
References: https://lists.freedesktop.org/archives/intel-gfx/2018-June/169315.html
References: https://bugs.freedesktop.org/show_bug.cgi?id=21230
Fixes: e2c8b870

 ("drm/i915: Use atomic helpers for suspend, v2.")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717174216.22252-1-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

There's a race between idling the engine and finishing off the last
tasklet (as we may kick the tasklets after declaring an individual
engine idle). However, since we do not need to access the device until
we try to submit to the ELSP register (processing the CSB just requires
normal CPU access to the HWSP, and when idle we should not need to
submit!) we can defer the assertion unto that point. The assertion is
still useful as it does verify that we do hold the longterm GT wakeref
taken from request allocation until request completion.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107274
Fixes: 9512f985

 ("drm/i915/execlists: Direct submission of new requests (avoid tasklet/ksoftirqd)")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180719075029.28643-1-chris@chris-wilson.co.uk

If we call into the shrinker for direct relcaim inside kmalloc, it will
retire the requests. If we retire the vma->last_active while processing a
new i915_vma_move_to_active() we can upset the delicate bookkeeping
required for the cache. After the possible invocation of the shrinker, we
need to double check the vma->last_active is still valid.

Fixes: 8b293eb5 ("drm/i915: Track the last-active inside the i915_vma")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105600#c39


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180719072206.16015-1-chris@chris-wilson.co.uk

We make a decision at module load whether to use the GuC backend or not,
but lose that setup across set-wedge. Currently, the guc doesn't
override the engine->set_default_submission hook letting execlists sneak
back in temporarily on unwedging leading to an unbalanced park/unpark.

v2: Remove comment about switching back temporarily to execlists on
guc_submission_disable(). We currently only call disable on shutdown,
and plan to also call disable before suspend and reset, in which case we
will either restore guc submission or mark the driver as wedged, making
the reset back to execlists pointless.
v3: Move reset.prepare across

Fixes: 63572937

 ("drm/i915/execlists: Flush pending preemption events during reset")
Testcase: igt/drv_module_reload/basic-reload-inject
Testcase: igt/gem_eio
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717202932.1423-1-chris@chris-wilson.co.uk

RC model has these parameters that correspond with each of
15 ranges of RC buffer threshold value in the RC model.
The three elements are range_min_qp, range_max_qp and
range_bpg_offset.

Add the Rate Control range values for eDP/MIPI and DP case.
The actual values are calculated usung a helper function.
This patch adds the shifts to registers where the value will
be written during atomic commit.

v2:
- Use _MMIO_PIPE() instead of _MMIO(_PICK()) (Manasi)
- Combine shifts (Manasi)

Cc: Jose Souza <jose.souza@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1531861861-10950-4-git-send-email-anusha.srivatsa@intel.com

Add register defines and  shifts that control the RC buffer threshold
between encoder and decoder for eDP/MIPI and DP cases.

The actual values are calculated usung a helper function.
This patch adds the shifts to registers where the value will
be written during atomic commit.

v2:
- Use _MMIO_PIPE() instead of _MMIO_(_PICK()) (Manasi)
- Combine shifts (Manasi)

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1531861861-10950-3-git-send-email-anusha.srivatsa@intel.com

Display Stream Compression(DSC) has a set of Picture
Parameter Set(PPS) components that the encoder must
communicate to the decoder.

This patch adds register definitions to
the PPS parameters for eDP/MIPI case and Display Port.

v2:
- Use _MMIO_PIPE instead of _MMIO(_PICK()). (Manasi)
- Use DSC constants as arguments. (Manasi)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1531861861-10950-2-git-send-email-anusha.srivatsa@intel.com

The Picture Parameter Set metadata for DSC has to be sent
to the panel through secondary data packets. Add the error
correction registers, data registers and control registers
for the same.

The control registers for  transcoders A and B are already
defined and will be reused for Icelake purpose. This patch adds
Control register for EDP and transcoder C apart from adding the
PPS data and error registers.

v2: reuse MMIO_TRANS2 for _PPS_DATA and _PPS_ECC.
The  _MMIO_TRANS2(pipe, reg) macro definition takes care of the eDp case

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1531861861-10950-1-git-send-email-anusha.srivatsa@intel.com

It was originally introduced following the VESA spec in order to validate PSR.

However we found so many issues around sink_crc that instead of helping PSR
development it only brought another layer of trouble to the table.

So, sink_crc has been a black whole for us in question of time, effort and hope.

First of the problems is that HW statement is clear: "Do not attempt to use
aux communication with PSR enabled". So the main reason behind sink_crc is
already compromised.

For a while we had hope on the aux-mutex could workaround this problem on SKL+
platforms, but that mutex was not reliable, not tested,
and we shouldn't use according to HW engineers.

Also, nor source, nor sink designed and implemented the sink_crc to be used like
we are trying to use here.

Well, the sink side of things is also apparently not prepared for this
case. Each panel that we tried seemed to have a different behavior with same
code and same source.

So, for all the time we lost on trying to ducktape all these different issues
I believe it is now time to move PSR to a more reliable validation.
Maybe not a perfect one as we dreamed for this sink_crc, but at least more
reliable.

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705192528.30515-1-rodrigo.vivi@intel.com

If the driver is wedged, we skip idling the GPU. However, we may still
have a few requests still not retired following the wedging (since they
will be waiting for a background worker trying to acquire struct_mutex).
As we hold the struct_mutex, always do a quick request retirement in
order to flush the wedged path.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107257


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717084121.28185-1-chris@chris-wilson.co.uk

Our I915g (early gen3, the oldest machine we have in the farm) is still
reporting occasional incoherency performing the following operations:

  1) write through GGTT (indirect write into memory)
  2) write through either CPU or WC (direct write into memory)
  3) read from GGTT (indirect read)

Instead of reporting the value from (2), the read from GGTT reports the
earlier value written via the GGTT. We have made sure that the writes are
flushed from the CPU (commit 3a32497f ("drm/i915/selftests: Provide
full mb() around clflush") and commit add00e6d

 ("drm/i915: Flush the
WCB following a WC write")), but still see the error, just less
frequently. The only remaining cache that might be affected here is a
chipset cache, so flush that as well.

Testcase: igt/drv_selftest/live_coherency #gdg
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717092655.28417-1-chris@chris-wilson.co.uk

In the huge pages tests, we may have lots of objects being trapped on
the freelist as we hold the struct_mutex allowing the free worker no
opportunity to recover the backing store. We also have stricter
requirements and the desire for large contiguous pages, further
increasing the allocation pressure. To reduce the chance of running out
of memory, we could either drop the mutex and flush the free worker, or
we could release the backing store directly. We do the latter in this
patch for simplicity.

References: https://bugs.freedesktop.org/show_bug.cgi?id=107254


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717082334.18774-1-chris@chris-wilson.co.uk

We must be able to reset the GPU while we are waiting on it to perform
an eviction (unbinding an active vma). So attach a spinning request to a
target vma and try and it evict it from a thread to see if that blocks
indefinitely.

v2: Add a wait for the thread to start just in case that takes more than
10ms...
v3: complete() not completion_done() to signal the completion.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716134009.13143-1-chris@chris-wilson.co.uk

Inject a failure into preemption completion to pretend as if the HW
didn't successfully handle preemption and we are forced to do a reset in
the middle.

v2: Wait for preemption, to force testing with the missed preemption.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716132154.12539-1-chris@chris-wilson.co.uk

On reset/wedging, we cancel all pending replies from the HW and we also
want to cancel an outstanding preemption event. Since we use the same
function to cancel the pending replies for reset and for a preemption
event, we can simply clear the active tracking for all.

v2: Keep execlists_user_end() markup for wedging
v3: Move assignment to inline to hide the bare assignment.

Fixes: 60a94324

 ("drm/i915/execlists: Drop clear_gtiir() on GPU reset")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716125424.5715-1-chris@chris-wilson.co.uk

If we declare the driver wedged before the GPU truly is, then we may see
the GPU complete some CS events following our cancellation. This leaves
us quite confused as we deleted all the bookkeeping and thus complain
about the inconsistent state.

We can just ignore the remaining events and let the GPU idle by not
feeding it, and so avoid trying to racily overwrite shared state. We
rely on there being a full GPU reset before unwedging, giving us the
opportunity to reset the shared state.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107188


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716080332.32283-4-chris@chris-wilson.co.uk

On an aborted module load, we unwind and free our device private - but
we left a dangling pointer to our privates inside the pci_device. After
the attempted aborted unload, we may still get a call to i915_pci_remove()
when the module is removed, potentially chasing stale data.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716080332.32283-5-chris@chris-wilson.co.uk

Give in, since CI continues to incorrectly insist that KERN_NOTICE is a
warning and flags the timeout message as unwanted spam. At first, the
intention was to use the message to indicate which tests might warrant
an extended run, but virtually all tests require a timeout so it is
simply not as interesting as first thought.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103667


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180716080332.32283-6-chris@chris-wilson.co.uk

We're seeing "RPM wakelock ref not held during HW access" warning
otherwise. Since IRQs are synced for runtime suspend we can just disable
the wakeref asserts.

Reported-by: Marta Löfstedt <marta.lofstedt@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105710


Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180714173703.7894-1-chris@chris-wilson.co.uk


Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

With the new CSB processing code, we are not vulnerable to delayed
delivery of a pre-reset interrupt as we use the CSB status pointers in
the HWSP to decide if we need to parse any CSB events and no longer need
to wait for the first post-reset interrupt to be assured that the CSB
mmio registers are valid.

The new icl code to clear registers has a nasty lock inversion:
[   57.409776] ======================================================
[   57.409779] WARNING: possible circular locking dependency detected
[   57.409783] 4.18.0-rc4-CI-CI_DII_1137+ #1 Tainted: G     U  W
[   57.409785] ------------------------------------------------------
[   57.409788] swapper/6/0 is trying to acquire lock:
[   57.409790] 000000004f304ee5 (&engine->timeline.lock/1){-.-.}, at: execlists_submit_request+0x2b/0x1a0 [i915]
[   57.409841]
               but task is already holding lock:
[   57.409844] 00000000aad89594 (&(&rq->lock)->rlock#2){-.-.}, at: notify_ring+0x2b2/0x480 [i915]
[   57.409869]
               which lock already depends on the new lock.

[   57.409872]
               the existing dependency chain (in reverse order) is:
[   57.409876]
               -> #2 (&(&rq->lock)->rlock#2){-.-.}:
[   57.409900]        notify_ring+0x2b2/0x480 [i915]
[   57.409922]        gen8_cs_irq_handler+0x39/0xa0 [i915]
[   57.409943]        gen11_irq_handler+0x2f0/0x420 [i915]
[   57.409949]        __handle_irq_event_percpu+0x42/0x370
[   57.409952]        handle_irq_event_percpu+0x2b/0x70
[   57.409956]        handle_irq_event+0x2f/0x50
[   57.409959]        handle_edge_irq+0xe7/0x190
[   57.409964]        handle_irq+0x67/0x160
[   57.409967]        do_IRQ+0x5e/0x120
[   57.409971]        ret_from_intr+0x0/0x1d
[   57.409974]        _raw_spin_unlock_irqrestore+0x4e/0x60
[   57.409979]        tasklet_action_common.isra.5+0x47/0xb0
[   57.409982]        __do_softirq+0xd9/0x505
[   57.409985]        irq_exit+0xa9/0xc0
[   57.409988]        do_IRQ+0x9a/0x120
[   57.409991]        ret_from_intr+0x0/0x1d
[   57.409995]        cpuidle_enter_state+0xac/0x360
[   57.409999]        do_idle+0x1f3/0x250
[   57.410004]        cpu_startup_entry+0x6a/0x70
[   57.410010]        start_secondary+0x19d/0x1f0
[   57.410015]        secondary_startup_64+0xa5/0xb0
[   57.410018]
               -> #1 (&(&dev_priv->irq_lock)->rlock){-.-.}:
[   57.410081]        clear_gtiir+0x30/0x200 [i915]
[   57.410116]        execlists_reset+0x6e/0x2b0 [i915]
[   57.410140]        i915_reset_engine+0x111/0x190 [i915]
[   57.410165]        i915_handle_error+0x11a/0x4a0 [i915]
[   57.410198]        i915_hangcheck_elapsed+0x378/0x530 [i915]
[   57.410204]        process_one_work+0x248/0x6c0
[   57.410207]        worker_thread+0x37/0x380
[   57.410211]        kthread+0x119/0x130
[   57.410215]        ret_from_fork+0x3a/0x50
[   57.410217]
               -> #0 (&engine->timeline.lock/1){-.-.}:
[   57.410224]        _raw_spin_lock_irqsave+0x33/0x50
[   57.410256]        execlists_submit_request+0x2b/0x1a0 [i915]
[   57.410289]        submit_notify+0x8d/0x124 [i915]
[   57.410314]        __i915_sw_fence_complete+0x81/0x250 [i915]
[   57.410339]        dma_i915_sw_fence_wake+0xd/0x20 [i915]
[   57.410344]        dma_fence_signal_locked+0x79/0x200
[   57.410368]        notify_ring+0x2ba/0x480 [i915]
[   57.410392]        gen8_cs_irq_handler+0x39/0xa0 [i915]
[   57.410416]        gen11_irq_handler+0x2f0/0x420 [i915]
[   57.410421]        __handle_irq_event_percpu+0x42/0x370
[   57.410425]        handle_irq_event_percpu+0x2b/0x70
[   57.410428]        handle_irq_event+0x2f/0x50
[   57.410432]        handle_edge_irq+0xe7/0x190
[   57.410436]        handle_irq+0x67/0x160
[   57.410439]        do_IRQ+0x5e/0x120
[   57.410445]        ret_from_intr+0x0/0x1d
[   57.410449]        cpuidle_enter_state+0xac/0x360
[   57.410453]        do_idle+0x1f3/0x250
[   57.410456]        cpu_startup_entry+0x6a/0x70
[   57.410460]        start_secondary+0x19d/0x1f0
[   57.410464]        secondary_startup_64+0xa5/0xb0
[   57.410466]
               other info that might help us debug this:

[   57.410471] Chain exists of:
                 &engine->timeline.lock/1 --> &(&dev_priv->irq_lock)->rlock --> &(&rq->lock)->rlock#2

[   57.410481]  Possible unsafe locking scenario:

[   57.410485]        CPU0                    CPU1
[   57.410487]        ----                    ----
[   57.410490]   lock(&(&rq->lock)->rlock#2);
[   57.410494]                                lock(&(&dev_priv->irq_lock)->rlock);
[   57.410498]                                lock(&(&rq->lock)->rlock#2);
[   57.410503]   lock(&engine->timeline.lock/1);
[   57.410506]
                *** DEADLOCK ***

[   57.410511] 4 locks held by swapper/6/0:
[   57.410514]  #0: 0000000074575789 (&(&dev_priv->irq_lock)->rlock){-.-.}, at: gen11_irq_handler+0x8a/0x420 [i915]
[   57.410542]  #1: 000000009b29b30e (rcu_read_lock){....}, at: notify_ring+0x1a/0x480 [i915]
[   57.410573]  #2: 00000000aad89594 (&(&rq->lock)->rlock#2){-.-.}, at: notify_ring+0x2b2/0x480 [i915]
[   57.410601]  #3: 000000009b29b30e (rcu_read_lock){....}, at: submit_notify+0x35/0x124 [i915]
[   57.410635]
               stack backtrace:
[   57.410640] CPU: 6 PID: 0 Comm: swapper/6 Tainted: G     U  W         4.18.0-rc4-CI-CI_DII_1137+ #1
[   57.410644] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP, BIOS ICLSFWR1.R00.2222.A01.1805300339 05/30/2018
[   57.410650] Call Trace:
[   57.410652]  <IRQ>
[   57.410657]  dump_stack+0x67/0x9b
[   57.410662]  print_circular_bug.isra.16+0x1c8/0x2b0
[   57.410666]  __lock_acquire+0x1897/0x1b50
[   57.410671]  ? lock_acquire+0xa6/0x210
[   57.410674]  lock_acquire+0xa6/0x210
[   57.410706]  ? execlists_submit_request+0x2b/0x1a0 [i915]
[   57.410711]  _raw_spin_lock_irqsave+0x33/0x50
[   57.410741]  ? execlists_submit_request+0x2b/0x1a0 [i915]
[   57.410769]  execlists_submit_request+0x2b/0x1a0 [i915]
[   57.410774]  ? _raw_spin_unlock_irqrestore+0x39/0x60
[   57.410804]  submit_notify+0x8d/0x124 [i915]
[   57.410828]  __i915_sw_fence_complete+0x81/0x250 [i915]
[   57.410854]  dma_i915_sw_fence_wake+0xd/0x20 [i915]
[   57.410858]  dma_fence_signal_locked+0x79/0x200
[   57.410882]  notify_ring+0x2ba/0x480 [i915]
[   57.410907]  gen8_cs_irq_handler+0x39/0xa0 [i915]
[   57.410933]  gen11_irq_handler+0x2f0/0x420 [i915]
[   57.410938]  __handle_irq_event_percpu+0x42/0x370
[   57.410943]  handle_irq_event_percpu+0x2b/0x70
[   57.410947]  handle_irq_event+0x2f/0x50
[   57.410951]  handle_edge_irq+0xe7/0x190
[   57.410955]  handle_irq+0x67/0x160
[   57.410958]  do_IRQ+0x5e/0x120
[   57.410962]  common_interrupt+0xf/0xf
[   57.410965]  </IRQ>
[   57.410969] RIP: 0010:cpuidle_enter_state+0xac/0x360
[   57.410972] Code: 44 00 00 31 ff e8 84 93 91 ff 45 84 f6 74 12 9c 58 f6 c4 02 0f 85 31 02 00 00 31 ff e8 7d 30 98 ff e8 e8 0e 94 ff fb 4c 29 fb <48> ba cf f7 53 e3 a5 9b c4 20 48 89 d8 48 c1 fb 3f 48 f7 ea b8 ff
[   57.411015] RSP: 0018:ffffc90000133e90 EFLAGS: 00000216 ORIG_RAX: ffffffffffffffdd
[   57.411023] RAX: ffff8804ae748040 RBX: 000000000002a97d RCX: 0000000000000000
[   57.411029] RDX: 0000000000000046 RSI: ffffffff82141263 RDI: ffffffff820f05a7
[   57.411035] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
[   57.411041] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8229f078
[   57.411045] R13: ffff8804ab2adfa8 R14: 0000000000000000 R15: 0000000d5de092e3
[   57.411052]  do_idle+0x1f3/0x250
[   57.411055]  cpu_startup_entry+0x6a/0x70
[   57.411059]  start_secondary+0x19d/0x1f0
[   57.411064]  secondary_startup_64+0xa5/0xb0

The easiest remedy is to remove the defunct code.

Fixes: ff047a87 ("drm/i915/icl: Correctly clear lost ctx-switch interrupts across reset for Gen11")
References: fd8526e5

 ("drm/i915/execlists: Trust the CSB")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713203529.1973-3-chris@chris-wilson.co.uk

Inside intel_engine_is_idle(), we flush the tasklet to ensure that is
being run in a timely fashion (ksoftirqd has taught us to expect the
worst). However, if we are in the middle of reset, the HW may not yet be
ready to execute the submission tasklet and so we must respect the
disable flag.

Fixes: dd0cf235

 ("drm/i915: Speed up idle detection by kicking the tasklets")
Testcase: igt/drv_selftest/live_hangcheck
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713203529.1973-2-chris@chris-wilson.co.uk

Knowing the boundary of each subtest can be instrumental in digesting
the voluminous trace output and finding the critical piece of
information.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713203529.1973-1-chris@chris-wilson.co.uk

Hopefully the final hack to get guc fault-injection happy before we can
clean it up again, starting from a known good baseline...

[  383.017530] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
[  383.017556] Oops: 0000 [#1] PREEMPT SMP PTI
[  383.017566] CPU: 7 PID: 4725 Comm: drv_module_relo Tainted: G     U            4.18.0-rc4-CI-CI_DRM_4485+ #1
[  383.017581] Hardware name: Micro-Star International Co., Ltd. MS-7B54/Z370M MORTAR (MS-7B54), BIOS 1.10 12/28/2017
[  383.017664] RIP: 0010:guc_stage_desc_pool_destroy+0x17/0xe0 [i915]
[  383.017674] Code: 59 a0 c6 05 02 59 18 00 01 e8 5e 01 c3 e0 eb b1 0f 1f 00 53 48 89 fb 48 81 c7 90 02 00 00 e8 60 64 45 e1 48 8b 83 80 02 00 00 <48> 8b 80 a0 00 00 00 48 8b 90 68 02 00 00 48 83 ea 01 48 81 fa ff
[  383.017771] RSP: 0018:ffffc900004bbdd0 EFLAGS: 00010282
[  383.017782] RAX: 0000000000000000 RBX: ffff88012ff41300 RCX: 0000000000000000
[  383.017794] RDX: 0000000000000000 RSI: ffffc900004bbd80 RDI: 0000000000000000
[  383.017805] RBP: ffff88012ff40000 R08: 00000000d876ee11 R09: 0000000000000000
[  383.017817] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88012ff47770
[  383.017828] R13: ffff88012ff40068 R14: ffff880264392ef8 R15: ffffffffa0639950
[  383.017840] FS:  00007fb9c18c8980(0000) GS:ffff8802663c0000(0000) knlGS:0000000000000000
[  383.017853] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  383.017864] CR2: 00000000000000a0 CR3: 00000001df6cc003 CR4: 00000000003606e0
[  383.017875] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  383.017887] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  383.017898] Call Trace:
[  383.017962]  intel_uc_fini+0x34/0xd0 [i915]
[  383.018020]  i915_gem_fini+0x5c/0x100 [i915]
[  383.018093]  i915_driver_unload+0xd2/0x110 [i915]
[  383.018150]  i915_pci_remove+0x10/0x20 [i915]
[  383.018165]  pci_device_remove+0x36/0xb0
[  383.018179]  device_release_driver_internal+0x185/0x250
[  383.018193]  driver_detach+0x35/0x70
[  383.018205]  bus_remove_driver+0x53/0xd0
[  383.018217]  pci_unregister_driver+0x25/0xa0
[  383.018232]  __se_sys_delete_module+0x162/0x210
[  383.018245]  ? do_syscall_64+0xd/0x190
[  383.018257]  do_syscall_64+0x55/0x190
[  383.018270]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  383.018282] RIP: 0033:0x7fb9c0f7c1b7
[  383.018290] Code: 73 01 c3 48 8b 0d d1 8c 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 8c 2c 00 f7 d8 64 89 01 48
[  383.018408] RSP: 002b:00007fffa01c2aa8 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[  383.018425] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb9c0f7c1b7
[  383.018440] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000560b96856d48
[  383.018454] RBP: 0000560b96856ce0 R08: 0000560b96856d4c R09: 00007fffa01c2ae8
[  383.018468] R10: 00007fffa01c1aa4 R11: 0000000000000206 R12: 0000560b954f7470

Testcase: igt/drv_module_reload/basic-reload-inject
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713172658.14070-1-chris@chris-wilson.co.uk

We're printing out which pins got a hotplug, so why not also print
out which pins detected the long pulse as opposed to a short pulse.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-9-ville.syrjala@linux.intel.com


Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

We're doing a pointless translation from hpd_pin to port simply for
passing the thing to long_pulse_detect(). Let's pass the hpd_pin
directly instead.

This removes the assumption that the hpd_pin and port always
match. The only other place where we make that assumption anymore
is intel_hpd_pin_default() and that's fine as it's what determines
the relationship between the two. If we ever get hardware where
the hpd pins are wired in more interesting ways it should be
trivial to handle from now on.

This should also fix the IS_CNL_WITH_PORT_F() case as that mapped
pin E back to port F and passed that to
spt_port_hotplug2_long_detect() which would always return false
for port F. Now that we pass in pin E directly it'll actually
do the right thing.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Fixes: cf53902f

 ("drm/i915/cnl: Add HPD support for Port F.")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-7-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Use the enum hpd_pin type when talking about HPD pins, and rename the
variable from a very nondescript 'i' to 'pin', a name we already
use in other parts of the code.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-6-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Instead of looping over ports and hpd_pins, let's loop over
the encoders when doing hotplug processing. And instead of
depending on dev_priv->irq_port[] to tell us whether the
encoder has the ->hpd_pulse() hook or not, we can just
check for that directly. So we can just nuke irq_port[] entirely.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-5-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Rather than looping over all the ports and picking the encoder based on
the port, let's just loop over all the encoders instead. Gets rid of
some irq_port[] usage, which is a bit of an eye sore.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-4-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Add intel_encoder_is_dig_port() to match intel_encoder_is_dp().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-3-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Add a convenience macro for iterating DP encoders.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-2-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

On gen8 and onwards, we can mark GPU accesses through the ppGTT as being
read-only, that is cause any GPU write onto that page to be discarded
(not triggering a fault). This is all that we need to finally support
the read-only flag for userptr!

v2: Check default address space for read only support as a proxy for the
user context/ppgtt.

Testcase: igt/gem_userptr_blits/readonly*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712191430.9269-1-chris@chris-wilson.co.uk

If the user created a read-only object, they should not be allowed to
circumvent the write protection using the pwrite ioctl.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-5-chris@chris-wilson.co.uk

If the user has created a read-only object, they should not be allowed
to circumvent the write protection by using a GGTT mmapping. Deny it.

Also most machines do not support read-only GGTT PTEs, so again we have
to reject attempted writes. Fortunately, this is known a priori, so we
can at least reject in the call to create the mmap (with a sanity check
in the fault handler).

v2: Check the vma->vm_flags during mmap() to allow readonly access.
v3: Remove VM_MAYWRITE to curtail mprotect()

Testcase: igt/gem_userptr_blits/readonly_mmap*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com> #v1
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-4-chris@chris-wilson.co.uk

GVT is not propagating the PTE bits, and is always setting the
read-write bit, thus breaking read-only support.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-3-chris@chris-wilson.co.uk