[Intel-gfx] [PATCH 1/4] drm/i915: Wait for inflight writes before checking intel_engine_is_idle()

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> On Wed, Mar 29, 2017 at 10:36:16PM +0100, Chris Wilson wrote:
>> Some GPUs may have writes inflight much longer than expected, so before
>> declaring the GPU is idle, try to flush them using any
>> engine->irq_seqno_barrier() if available. By allowing them to be
>> flushed, we can be a little more confident that the GPU really is idle
>> when we think it is!
>> 
>> References: https://bugs.freedesktop.org/show_bug.cgi?id=98836
>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> ---
>>  drivers/gpu/drm/i915/intel_engine_cs.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
>> index c76a64483d64..ff6d0e1d1306 100644
>> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
>> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
>> @@ -1074,6 +1074,10 @@ bool intel_engine_is_idle(struct intel_engine_cs *engine)
>>  {
>>  	struct drm_i915_private *dev_priv = engine->i915;
>>  
>> +	/* We have to allow time for writes to land from the GPU. */
>> +	if (engine->irq_seqno_barrier)
>> +		engine->irq_seqno_barrier(engine);
>> +
>
> Problem persists so ignore this patch. 2-4 are still a nice cleanup and
> worth persuing.

Patch 1 looked good too.

> -Chris
>
> -- 
> Chris Wilson, Intel Open Source Technology Centre
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