[Intel-gfx] [PATCH 14/20] drm/i915: Forcefully flush GuC log buffer on reset

[Goel, Akash]

On 8/12/2016 12:03 PM, Chris Wilson wrote:
> On Fri, Aug 12, 2016 at 11:55:17AM +0530, akash.goel at intel.com wrote:
>> From: Sagar Arun Kamble <sagar.a.kamble at intel.com>
>>
>> Before capturing the GuC logs as a part of error state, there should be a
>> force log buffer flush action sent to GuC before proceeding with GPU reset
>> and re-initializing GUC. There could be some data in the log buffer which is
>> yet to be captured and those logs would be particularly useful to understand
>> that why the GPU reset was initiated.
>>
>> Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
>> Signed-off-by: Akash Goel <akash.goel at intel.com>
>> ---
>>  drivers/gpu/drm/i915/i915_gpu_error.c      |  2 ++
>>  drivers/gpu/drm/i915/i915_guc_submission.c | 27 +++++++++++++++++++++++++++
>>  drivers/gpu/drm/i915/intel_guc.h           |  1 +
>>  3 files changed, 30 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
>> index 561b523..5e358e2 100644
>> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
>> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
>> @@ -1232,6 +1232,8 @@ static void i915_gem_capture_guc_log_buffer(struct drm_i915_private *dev_priv,
>>  	if (!dev_priv->guc.log.obj)
>>  		return;
>>
>> +	i915_guc_flush_logs(dev_priv);
>
> This is an invalid context for this function, flush_work() is illegal
> inside error capture.

Actually the concerned work item should not take much time for execution 
and also it doesn't acquire any such locks due to which it can get blocked.

Should there be no wait whatsoever in error capture ?
Will have to drop this patch.

Best regards
Akash
> -Chris
>