[Intel-gfx] [PATCH 1/1] drm/i915: skip the second CRC even for GEN 7 GPUs

[Jani Nikula]

On Thu, 16 May 2019, Maarten Lankhorst <maarten.lankhorst at linux.intel.com> wrote:
> Op 16-05-2019 om 07:58 schreef Harish Chegondi:
>> display_pipe_crc_irq_handler() skips the first CRC for all GPUs and the
>> second CRC for GEN8+ GPUs. The second CRC is invalid even for BYT which
>> is a GEN7 GPU. So, skip the second CRC even for GEN7 GPUs.
>>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Cc: Tomi Sarvela <tomi.p.sarvela at intel.com>
>> Cc: Petri Latvala <petri.latvala at intel.com>
>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>> Signed-off-by: Harish Chegondi <harish.chegondi at intel.com>
>> References: https://bugs.freedesktop.org/show_bug.cgi?id=103191
>> ---
>>  drivers/gpu/drm/i915/i915_irq.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>> index 233211fde0ea..3809e9f7fae2 100644
>> --- a/drivers/gpu/drm/i915/i915_irq.c
>> +++ b/drivers/gpu/drm/i915/i915_irq.c
>> @@ -1775,11 +1775,11 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
>>  	 * bonkers. So let's just wait for the next vblank and read
>>  	 * out the buggy result.
>>  	 *
>> -	 * On GEN8+ sometimes the second CRC is bonkers as well, so
>> +	 * On GEN7+ sometimes the second CRC is bonkers as well, so
>>  	 * don't trust that one either.
>>  	 */
>>  	if (pipe_crc->skipped <= 0 ||
>> -	    (INTEL_GEN(dev_priv) >= 8 && pipe_crc->skipped == 1)) {
>> +	    (INTEL_GEN(dev_priv) >= 7 && pipe_crc->skipped == 1)) {
>>  		pipe_crc->skipped++;
>>  		spin_unlock(&pipe_crc->lock);
>>  		return;
>
> I would be interested in the results, haswell is different from
> VLV. Has it ever been observed on that platform?

Good point. I looked at [1] which I presumed was on VLV, but it says
nothing about HSW.

BR,
Jani.



[1] https://bugs.freedesktop.org/show_bug.cgi?id=103191#c34


>

-- 
Jani Nikula, Intel Open Source Graphics Center