HDCP could be fused off, so not all GEN9+ platforms will support it.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Martin Peres <martin.peres@linux.intel.com>
Reviewed-by: NRamalingam C <ramalingam.c@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191026001323.216052-2-jose.souza@intel.com

The next patches are going to touch this registers so here already
fixing it for older registers and make it consistent with most of
the other registers in this file.

Cc: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NRadhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191026001323.216052-1-jose.souza@intel.com

Gen12 only support a single report format :
I915_OA_FORMAT_A32u40_A4u32_B8_C8
Signed-off-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 00a7f0d7 ("drm/i915/tgl: Add perf support on TGL")
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029142826.20014-1-lionel.g.landwerlin@intel.com

Our TGL CI platforms are running into cases where aux transactions have
failed to complete or declare a timeout well after the timeout limit
that the hardware is supposed to enforce.  From the logs it appears that
these failures arise when aux transactions happen after we've entered
DC6:

  <7> [622.523650] [drm:skl_enable_dc6 [i915]] Enabling DC6
  <7> [622.523685] [drm:gen9_set_dc_state [i915]] Setting DC state from 00 to 02
  ...
  <3> [622.535753] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout!
  <3> [622.547745] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout!
  <3> [622.559746] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout!
  <3> [622.571744] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout!
  <3> [622.583743] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout!
  <3> [622.583780] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp_aux_ch not done status 0xad400bff
  <7> [622.863725] [drm:drm_dp_dpcd_access] Too many retries, giving up. First error: -110

On TGL AUX B & C are in PG1 (managed by the DMC firmware) rather
than PG3 as they were on ICL, so allowing DC6 means the DMC firmware
might shut off the power wells behind our backs when we're trying to use
them.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025230623.27829-6-matthew.d.roper@intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

We reference DP AUX registers via the DP_AUX_CH_CTL() and
DP_AUX_CH_DATA() macros that calculate all the register offsets for us
automatically; there's no need to explicitly define every offset in
i915_reg.h if they're never going to be used by the driver code.

v2: Apparently GVT was directly using these raw definitions in a couple
    places.  Switch GVT code over to using our preferred macros.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>  #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20191026051226.30807-1-matthew.d.roper@intel.com

Execlists uses a scheduling quantum (a timeslice) to alternate execution
between ready-to-run contexts of equal priority. This ensures that all
users (though only if they of equal importance) have the opportunity to
run and prevents livelocks where contexts may have implicit ordering due
to userspace semaphores. However, not all workloads necessarily benefit
from timeslicing and in the extreme some sysadmin may want to disable or
reduce the timeslicing granularity.

The timeslicing mechanism can be compiled out^W^W disabled (but should
DCE!) with

	./scripts/config --set-val DRM_I915_TIMESLICE_DURATION 0
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029091632.26281-1-chris@chris-wilson.co.uk

Commit f2db53f1 ("drm/i915: Replace "_load" with "_probe"
consequently") deliberately left the name of the module parameter
unchanged as that would require a corresponding change on IGT size.
Now as the IGT side change has been submitted, complete the switch to
the "probe" nomenclature.
Suggested-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: NJanusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Michał Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029102036.6326-3-janusz.krzysztofik@linux.intel.com

Commit 50d84418 ("drm/i915: Add i915 to i915_inject_probe_failure")
introduced new functions unfortunately named incompatibly with rules
established by commit f2db53f1 ("drm/i915: Replace "_load" with
"_probe" consequently").  Fix it for consistency.
Suggested-by: NMichał Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: NJanusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Michał Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029102036.6326-2-janusz.krzysztofik@linux.intel.com

The change from the uapi coordinates to the internal coordinates
broke the cursor on i845/i865 due to src and dst getting swapped.
Fix it.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 3a612765 ("drm/i915: Remove cursor use of properties for coordinates")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028113036.27553-1-ville.syrjala@linux.intel.comReviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

The design of the OA unit has been split into several units. We now
have a global unit (OAG) and a render specific unit (OAR). This leads
to some changes on how we program things. Some details :

OAR:
  - has its own set of counter registers, they are per-context
    saved/restored
  - counters are not written to the circular OA buffer
  - a snapshot of the counters can be acquired with
    MI_RECORD_PERF_COUNT, or a single counter can be read with
    MI_STORE_REGISTER_MEM.

OAG:
  - has global counters that increment across context switches
  - counters are written into the circular OA buffer (if requested)

v2: Fix checkpatch warnings on code style (Lucas)
v3: (Umesh)
  - Update register from which tail, status and head are read
  - Update logic to sample context reports
  - Update whitelist mux and b counter regs
v4: Fix a bug when updating context image for new contexts (Umesh)
v5: Squash patch enabling save/restore of counters into context image

    We want this so we can preempt performance queries and keep the
    system responsive even when long running queries are ongoing. We
    avoid doing it for all contexts.

    - use LRI to modify context control (Chris)
    - use MASKED_FIELD to program just the masked bits (Chris)
    - disable save/restore of counters on cleanup (Chris)
v6: Do not use implicit parameters (Chris)

BSpec: 28727, 30021
Signed-off-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: NUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: NChris Wilson <chris.p.wilson@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025193746.47155-2-umesh.nerlige.ramappa@intel.com

Add helper macros for range and equality comparisons and use them to
check with whitelisted registers in oa configurations.
Signed-off-by: NUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025193746.47155-1-umesh.nerlige.ramappa@intel.com

We may be missing support for the mappable aperture on some platforms.
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-7-matthew.auld@intel.com

Since we have no way access it from the CPU. For such cases just
fallback to internal objects.
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-6-matthew.auld@intel.com

HWS placement restrictions can't just rely on HAS_LLC flag.
Signed-off-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-5-matthew.auld@intel.com

If the aperture is not available in HW we can't use a ggtt slot and wc
copy, so fall back to regular kmap.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NAbdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-4-matthew.auld@intel.com

We can't fence anything without aperture.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NStuart Summers <stuart.summers@intel.com>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-3-matthew.auld@intel.com

Skip both setup and cleanup of the aperture mapping if the HW doesn't
have an aperture bar.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-2-matthew.auld@intel.com

The following patches in the series will use it to avoid certain
operations when the mappable aperture is not available in HW.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029095856.25431-1-matthew.auld@intel.com

There is nothing to say that the obj->base.size is actually a multiple
of the block_size.

v2: Use round_up() as block_size is a power-of-two
Reported-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028220325.9325-1-chris@chris-wilson.co.uk

Currently we insert a arbitration point every 128MiB during a blitter
copy. At 8GiB/s, this is around 30ms. This is a little on the large side
if we need to inject a high priority work, so reduced it down to 8MiB or
roughly 1ms.

v2: Don't forget both fill/copy.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028203012.14566-1-chris@chris-wilson.co.uk

While processing CSB there is no need to look at GuC submission
settings, just check if engine is configured for execlists mode.

While today GuC submission is disabled it's settings are still
based on modparam values that might not correctly reflect actual
submission status in case of any fallback. Until that is fully
fixed, use alternate method to confirm that engine really runs in
execlists mode by comparing set_default_submission vfunc.

v2: add other immediate use of new helper
Signed-off-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: NJanusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028164520.31772-1-michal.wajdeczko@intel.com

smatch complains about
drivers/gpu/drm/i915//display/intel_display.c:14403 intel_set_dp_tp_ctl_normal() error: uninitialized symbol 'conn'.
because it has no way to determine that the loop must have an entry.
Tell the static analysers to ignore the local, it will always be set.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028142652.1987-2-chris@chris-wilson.co.uk

Keep smatch quiet,

drivers/gpu/drm/i915//gem/selftests/i915_gem_context.c:1268 __igt_ctx_sseu() error: uninitialized symbol 'ret'.
drivers/gpu/drm/i915//gem/selftests/i915_gem_context.c:1280 __igt_ctx_sseu() error: uninitialized symbol 'ret'.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028142652.1987-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915//gt/selftest_engine_heartbeat.c:255 live_heartbeat_fast() error: uninitialized symbol 'err'.
drivers/gpu/drm/i915//gt/selftest_engine_heartbeat.c:320 live_heartbeat_off() error: uninitialized symbol 'err'.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025135943.12524-2-chris@chris-wilson.co.uk

The request's timeline will only contain requests from this context, in
order of execution. Therefore, we can simply look back along this
timeline to find the currently executing request.

If we do find that the current context has completed its last request,
that does not imply that all requests are completed in the context, so
only advance the ring->head up to the end of the known completions!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028124125.25176-1-chris@chris-wilson.co.uk

As we use hard coded offsets for a few locations within the context
image, include those in the selftests to assert that they are valid.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028121803.29408-1-chris@chris-wilson.co.uk

We're currently only processing AUX interrupts on the combo ports; make
sure we handle the TC ports as well.

v2: Drop stale comment

Fixes: f663769a ("drm/i915/tgl: initialize TC and TBT ports")
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024173023.22113-1-matthew.d.roper@intel.com

Iterate over all user-accessible render engines when checking whether
they can be adjusted for sseu.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027225808.19437-2-chris@chris-wilson.co.uk

Use any blitter engine at random for prefilling the memory region.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027225808.19437-5-chris@chris-wilson.co.uk

Since the rps is tied to its intel_gt, use that backpointer to find the
right engine rather than delving into i915.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027175505.25470-1-chris@chris-wilson.co.uk

Select a random user accessible engine for checking coherency results.
While we should check all engines, we use a random selection so that
over repeated runs we cover all.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027225808.19437-4-chris@chris-wilson.co.uk

Add definition for block 56, the compression parameters.

v2: add missing slice_height (Vandita)

Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: NVandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024075608.11511-1-jani.nikula@intel.com

Check all user accessible engines that can blit work with our blitter
client.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027225808.19437-3-chris@chris-wilson.co.uk

As we are inside the gt, we have a local gt->engine[] lookup we should
be using in preference over the i915->engine[] copy.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027225808.19437-1-chris@chris-wilson.co.uk

We need to verify that our blitter routines perform as expected, so
measure it.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028112207.5464-1-chris@chris-wilson.co.uk

Add CHICKEN_TRANS definition for transcoder D.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024122138.25065-2-ville.syrjala@linux.intel.comReviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>

Make CHICKEN_TRANS() a bit less special looking by using _PICK().
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024122138.25065-1-ville.syrjala@linux.intel.comReviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>

ips uses clock delays as opposed to rps frequency bins. To fit the
delays into the same rps calculations, we need to invert the ips delays.

Fixes: 3e7abf81 ("drm/i915: Extract GT render power state management")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191026200917.1780-1-chris@chris-wilson.co.uk

We would like some freedom to break the user API/ABI for future HW but
yet still expose the driver for upstream development on that HW.
Currently, we have the i915.force_probe module parameter to avoid binding
to HW while the driver is under development, but that is still a little
too soft with respect to the stringent no-regression rules if we also
plan to be redesigning the uAPI to go along with the new HW.

To allow the uAPI to be changed during development, only expose that API
and in development HW under STAGING (and BROKEN). Hopefully, making it
explicit that such interfaces to that HW are under development and not
to be blindly enabled by distributions.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Acked-by: NDave Airlie <airlied@redhat.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191027154314.11139-1-chris@chris-wilson.co.uk

Pull the memory region bookkeeping into its file. Let's start clean and
see how long it lasts!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191026202032.4371-1-chris@chris-wilson.co.uk