Just avoid the additional read in case DP_TP_CTL is enabled:
read it once and save the value.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030012448.14937-5-lucas.demarchi@intel.com

For MST on Tiger Lake there are different moments when we need to
configure the transcoder clock select. For the first link this is in step
7.a of the spec, before training the link.  For additional streams this
should be done as part of step 8.b after programming receiver VC Payload
ID.

Bspec: 49190
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030012448.14937-4-lucas.demarchi@intel.com

Wrap drm_atomic_get_old_connector_state so we can get the
intel_digital_connector_state and make it easier to migrate to intel
types.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030012448.14937-3-lucas.demarchi@intel.com

The same macro as for_each_new_connector_in_state() but it uses
intel/i915 types instead of the drm ones.
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NMika Kahola <mika.kahola@intel.com>
Reviewed-by: NLucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190823082055.5992-11-lucas.demarchi@intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20191030012448.14937-2-lucas.demarchi@intel.com

Lots of redundant assignments inside intel_primary_plane_create().
Get rid of them.

v2: Rebase due to fp16 landing
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJuha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-8-ville.syrjala@linux.intel.com

Let's try to keep the pixel format arrays somewhat sorted:
1. RGB before YUV
2. smaller bpp before larger bpp
3. X before A
4. RGB before BGR
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJuha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-7-ville.syrjala@linux.intel.com

ICL+ again supports alpha blending with 10bpc pixel formats.
Expose them.

v2: Add all the stuff I missed earlier!
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJuha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-6-ville.syrjala@linux.intel.com

VLV/CHV sprite planes also support the C8 format. Let's expose that.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-5-ville.syrjala@linux.intel.com

CHV pipe B sprites gained support for the 10bpc X/ARGB pixel formats.
On VLV and CHV pipe A/C these are only supported by the primary
plane. Add the require bits to expose the new formats.

v2: Reorder the formats for consistency
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-4-ville.syrjala@linux.intel.com

Currently we expose VLV/CHV alpha blending only on the sprite
planes, but the primary planes can do it as well. Let's flip
it on.

v2: Rebase due to fp16 landing
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-3-ville.syrjala@linux.intel.com

SNB-BDW support 10:10:10 formats on the sprite planes. Let's expose
them.

v2: Rebase due to fp16 landing
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJuha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-2-ville.syrjala@linux.intel.com

Sometimes Icelake forgets to reset the CSB pointers on a GPU reset,
leading to it carry on updating the old tail of the buffer.

<0>[  618.138490] i915_sel-5636    3d..1 673425465us : trace_ports: vecs0: submit { 14de2:504, 0:0 }
<0>[  618.138490] i915_sel-5636    3.... 673425493us : intel_engine_reset: vecs0 flags=100
<0>[  618.138490] i915_sel-5636    3.... 673425493us : execlists_reset_prepare: vecs0: depth<-0
<0>[  618.138490] i915_sel-5636    3.... 673425493us : intel_engine_stop_cs: vecs0
<0>[  618.138490] i915_sel-5636    3.... 673425523us : __intel_gt_reset: engine_mask=40
<0>[  618.138490] i915_sel-5636    3.... 673425568us : execlists_reset: vecs0
<0>[  618.138490] i915_sel-5636    3d..1 673425568us : process_csb: vecs0 cs-irq head=1, tail=2
<0>[  618.138490] i915_sel-5636    3d..1 673425568us : process_csb: vecs0 csb[2]: status=0x00000001:0x40000000
<0>[  618.138490] i915_sel-5636    3d..1 673425569us : trace_ports: vecs0: promote { 14de2:504*, 0:0 }
<0>[  618.138490] i915_sel-5636    3d..1 673425570us : __i915_request_reset: vecs0 rq=14de2:504, guilty? yes
<0>[  618.138490] i915_sel-5636    3d..1 673425571us : __execlists_reset: vecs0 replay {head:2de0, tail:2e48}
<0>[  618.138490] i915_sel-5636    3d..1 673425572us : __i915_request_unsubmit: vecs0 fence 14de2:504, current 503
<0>[  618.138490] i915_sel-5636    3.... 673435544us : intel_engine_cancel_stop_cs: vecs0
<0>[  618.138490] i915_sel-5636    3.... 673435544us : process_csb: vecs0 cs-irq head=11, tail=11
<0>[  618.138490] i915_sel-5636    3d..1 673435545us : __i915_request_submit: vecs0 fence 14de2:504, current 503
<0>[  618.138490] i915_sel-5636    3d..1 673435546us : __execlists_submission_tasklet: vecs0: queue_priority_hint:-2147483648, submit:yes
<0>[  618.138490] i915_sel-5636    3d..1 673435548us : trace_ports: vecs0: submit { 14de2:504*, 0:0 }
<0>[  618.138490] i915_sel-5636    3.... 673435549us : execlists_reset_finish: vecs0: depth->0
<0>[  618.138490] ksoftirq-21      2..s. 673435592us : process_csb: vecs0 cs-irq head=11, tail=3
<0>[  618.138490] ksoftirq-21      2..s. 673435593us : process_csb: vecs0 csb[0]: status=0x00000001:0x40000000
<0>[  618.138490] ksoftirq-21      2..s. 673435594us : trace_ports: vecs0: promote { 14de2:504*, 0:0 }
<0>[  618.138490] ksoftirq-21      2..s. 673435596us : process_csb: vecs0 csb[1]: status=0x00000018:0x40000040
<0>[  618.138490] ksoftirq-21      2..s. 673435597us : trace_ports: vecs0: completed { 14de2:504*, 0:0 }
<0>[  618.138490] ksoftirq-21      2..s. 673435612us : process_csb: process_csb:2188 GEM_BUG_ON(!i915_request_completed(*execlists->active) && !reset_in_progress(execlists))

After the reset, we do another clflush before checking the CSB to be
sure we see whatever was left in the CSB prior to the reset. So it is
unlikely to be an incoherent view of the CSB, and more likely that
Icelake didn't reset its pointers.

References: 582a6f90 ("drm/i915/execlists: Add a paranoid flush of the CSB pointers upon reset")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191104135307.21083-1-chris@chris-wilson.co.uk

Add another for_each style macro to the pile of custom looping macros.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101134333.11612-1-jani.nikula@intel.com

Since the execlists_active() is no longer protected by the
engine->active.lock, we need to protect the request pointer with RCU to
prevent it being freed as we evaluate whether or not we need to preempt.

Fixes: df403069 ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock")
Fixes: 13ed13a4 ("drm/i915: Don't set queue_priority_hint if we don't kick the submission")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191104090158.2959-2-chris@chris-wilson.co.uk

The counter is removed from the pm wakeref count, but it remains intact
so that we can restore it upon resume. Ergo inside suspend, it may have
a value.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191104090158.2959-1-chris@chris-wilson.co.uk

Filter out warnings for the kernel context that is used to flush
inactive contexts, as they do no not pose a risk.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101082919.21122-1-chris@chris-wilson.co.uk

Check that the context's ring register state still matches our
expectations prior to execution.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191102125739.24626-1-chris@chris-wilson.co.uk

Flushing the outer i915_active is not enough, as we need the barrier to
be applied across all the active dma_fence callbacks. So we must
serialise with each outstanding fence.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112096
References: f79520bb ("drm/i915/selftests: Synchronize checking active status with retirement")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101181022.25633-1-chris@chris-wilson.co.uk

Avoid

drivers/gpu/drm/i915/i915_perf.c:2442:85: warning: dubious: x | !y

simply by inverting the predicate and reversing the ternary.

v2: Move the long lines into their own function so there is no confusion
on operator precedence.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: NUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101192116.12647-1-chris@chris-wilson.co.uk

Call suspend_prepare first so that we don't leave GuC so confused.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101174405.7389-1-chris@chris-wilson.co.uk

Currently we shutdown rc6 during i915_gem_resume() but this is called
during the preparation phase (i915_drm_prepare) for all suspend paths,
but we only want to shutdown rc6 for S3+. Move the actual shutdown to
i915_gem_suspend_late().

We then need to differentiate between suspend targets, to distinguish S0
(s2idle) where the device is kept awake but needs to be in a low power
mode (the same as runtime suspend) from the device suspend levels where
we lose control of HW and so must disable any HW access to dangling
memory.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111909
Fixes: c1132367 ("drm/i915: Extract GT render sleep (rc6) management")
Testcase: igt/gem_exec_suspend/power-S0
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101141009.15581-4-chris@chris-wilson.co.uk

We already track the debugfs user_forcewake on the GT, so it is natural
to pull the suspend/resume handling under gt/ as well.
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/20191101141009.15581-3-chris@chris-wilson.co.uk

As we already do reload the kernel context in intel_gt_resume, repeating
that action inside i915_gem_resume() as well is redundant.
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/20191101141009.15581-2-chris@chris-wilson.co.uk

Assume all responsibility for operating on the HW to sanitize the GT
state upon load/resume in intel_gt_sanitize() itself.
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/20191101141009.15581-1-chris@chris-wilson.co.uk

Our timelines are currently contained within an intel_gt, and we only
need to perform list/spinlock initialisation, so we can pull the
intel_timelines_init() into our intel_gt_init_early().
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101130406.4142-1-chris@chris-wilson.co.uk

Now that we split plane_state which I didn't want to do yet, we can
program the slave plane without requiring the master plane.

This is useful for programming bigjoiner slave planes as well. We
will no longer need the master's plane_state.

Changes since v1:
- set src/dst rectangles after copy_uapi_to_hw_state.
Changes since v2:
- Use the correct color_plane for pre-gen11 by using planar_linked_plane != NULL.
- Use drm_format_info_is_yuv_semiplanar in skl_plane_check() to fix gen11+.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-12-maarten.lankhorst@linux.intel.com

Splitting plane state is easier than splitting crtc_state,
before plane check we copy the drm properties to hw so we can
do the same in bigjoiner later on.

We copy the state after we did all the modeset handling, but fortunately
i915 seems to be split correctly and nothing during modeset looks
at plane_state.

Changes since v1:
- Do not clear hw state on duplication.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-11-maarten.lankhorst@linux.intel.com

Split up plane_state->base to uapi. This is done using the following patch,
ran after the previous commit that splits out any hw references:

@@
struct intel_plane_state *T;
identifier x;
@@
-T->base.x
+T->uapi.x

@@
struct intel_plane_state *T;
@@
-T->base
+T->uapi
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-10-maarten.lankhorst@linux.intel.com

Split up plane_state->base to hw. This is done using the following patch:

@@
struct intel_plane_state *T;
identifier x =~ "^(crtc|fb|alpha|pixel_blend_mode|rotation|color_encoding|color_range)$";
@@
-T->base.x
+T->hw.x
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-9-maarten.lankhorst@linux.intel.com

get_crtc_from_states() is called before plane_state is copied to uapi,
so use the uapi state there.

intel_legacy_cursor_update() could probably get away with looking at
the hw state, but for clarity always look at the uapi state.

Changes since v1:
- Convert entirety of intel_legacy_cursor_update (Ville).
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-8-maarten.lankhorst@linux.intel.com

Prepare to split up hw and uapi machinally, by adding a uapi and
hw alias. We will remove the base in a bit. This is a split from the
original uapi/hw patch, which did it all in one go.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-7-maarten.lankhorst@linux.intel.comReviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Now that we separated everything into uapi and hw, it's
time to make the split definitive. Remove the union and
make a copy of the hw state on modeset and fastset.

Color blobs are copied in crtc atomic_check(), right
before color management is checked.

Changes since v1:
- Copy all blobs immediately after drm_atomic_helper_check_modeset().
- Clear crtc_state->hw on disable, instead of using clear_intel_crtc_state().
Changes since v2:
- Use intel_crtc_free_hw_state + clear in intel_crtc_disable_noatomic().
- Make a intel_crtc_prepare_state() function that clears the crtc_state
  and copies hw members.
- Remove setting uapi.adjusted_mode, we now have a direct call to
  drm_calc_timestamping_constants().
Changes since v3:
- Rename prefix copy_hw_to_uapi_state() with intel_crtc.
- Copy color blobs to uapi as well.
- Add a intel_crtc_copy_uapi_to_hw_state_nomodeset() function for clarity.
Changes since v4:
- Copy hw.adjusted_mode back to uapi.adjusted_mode, to shut up
  the call to drm_calc_timestamping_constants() in
  drm_atomic_helper_update_legacy_modeset_state().
- Use drm_property_replace_blob (Ville).
Changes since v5:
- Use hw->mode in intel_modeset_readout_hw_state(). (Ville)
- Copy to uapi.mode using drm_atomic_set_mode_for_crtc(). (Ville)
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-6-maarten.lankhorst@linux.intel.comReviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Split up crtc_state->base to uapi. This is done using the following patch,
ran after the previous commit that splits out any hw references:

@@
struct intel_crtc_state *T;
@@
-T->base
+T->uapi
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-5-maarten.lankhorst@linux.intel.com

Split up crtc_state->base to hw where appropriate. This is done using the following patch:

@@
struct intel_crtc_state *T;
identifier x =~ "^(active|enable|degamma_lut|gamma_lut|ctm|mode|adjusted_mode)$";
@@
-T->base.x
+T->hw.x

@@
struct drm_crtc_state *T;
identifier x =~ "^(active|enable|degamma_lut|gamma_lut|ctm|mode|adjusted_mode)$";
@@
-to_intel_crtc_state(T)->base.x
+to_intel_crtc_state(T)->hw.x
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-4-maarten.lankhorst@linux.intel.com

intel_get_load_detect_pipe() needs to set uapi active,
uapi enable is set by the call to drm_atomic_set_mode_for_crtc(),
so we can remove it.

intel_pipe_config_compare() needs to look at hw state, but I didn't
change spatch to look at it. It's easy enough to do manually.

intel_atomic_check() definitely needs to check for uapi enable,
otherwise intel_modeset_pipe_config cannot copy uapi state to hw.

Changes since v1:
- Actually set uapi.active in get_load_detect_pipe().
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-3-maarten.lankhorst@linux.intel.com

Prepare to split up hw and uapi machinally, by adding a uapi and
hw alias. We will remove the base in a bit. This is a split from the
original uapi/hw patch, which did it all in one go.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-2-maarten.lankhorst@linux.intel.comReviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

We are still looking at drm_crtc_state in a few places, convert those
to use intel_crtc_state instead.

Changes since v1:
- Move to before uapi/hw split.
- Add hunks for intel_pm.c as well.
Changes since v2:
- Incorporate Ville's feedback.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031112610.27608-1-maarten.lankhorst@linux.intel.com

Vanshidhar Konda asked for the simplest test "to verify that the kernel
can submit and hardware can execute batch buffers on all the command
streamers in parallel." We have a number of tests in userspace that
submit load to each engine and verify that it is present, but strictly
we have no selftest to prove that the kernel can _simultaneously_
execute on all known engines. (We have tests to demonstrate that we can
submit to HW in parallel, but we don't insist that they execute in
parallel.)

v2: Improve the igt_spinner support for older gen.
Suggested-by: NVanshidhar Konda <vanshidhar.r.konda@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Vanshidhar Konda <vanshidhar.r.konda@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NVanshidhar Konda <vanshidhar.r.konda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101101528.10553-1-chris@chris-wilson.co.uk

Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

An interesting observation made with our parallel selftests was that on
our small/single cpu systems we would call kthread_stop() before the
kthreads were spawned. If this happens, the kthread is never run at all;
completely bypassing the test.

A simple yield() from the parent will ensure that all children have the
opportunity to start before we reap them.
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/20191101084940.31838-1-chris@chris-wilson.co.uk