[Intel-gfx] [PATCH v3 1/2] drm/i915/uc: Start preparing GuC/HuC for reset

[Sagar Arun Kamble]

On 3/5/2018 8:13 PM, Chris Wilson wrote:
> Quoting Michal Wajdeczko (2018-03-05 14:29:16)
>> Right after GPU reset there will be a small window of time during which
>> some of GuC/HuC fields will still show state before reset. Let's start
>> to fix that by sanitizing firmware status as we will use it shortly.
>>
>> v2: s/reset_prepare/prepare_to_reset (Michel)
>>      don't forget about gem_sanitize path (Daniele)
>> v3: rebased
>>
>> Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Michel Thierry <michel.thierry at intel.com>
>> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_gem.c    |  5 ++++-
>>   drivers/gpu/drm/i915/intel_guc.h   |  5 +++++
>>   drivers/gpu/drm/i915/intel_huc.h   |  5 +++++
>>   drivers/gpu/drm/i915/intel_uc.c    | 14 ++++++++++++++
>>   drivers/gpu/drm/i915/intel_uc.h    |  1 +
>>   drivers/gpu/drm/i915/intel_uc_fw.h |  6 ++++++
>>   6 files changed, 35 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
>> index a5bd073..aedb17d 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -2981,6 +2981,7 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv)
>>          }
>>   
>>          i915_gem_revoke_fences(dev_priv);
>> +       intel_uc_prepare_to_reset(dev_priv);
>>   
>>          return err;
>>   }
>> @@ -4882,8 +4883,10 @@ void i915_gem_sanitize(struct drm_i915_private *i915)
>>           * it may impact the display and we are uncertain about the stability
>>           * of the reset, so this could be applied to even earlier gen.
>>           */
>> -       if (INTEL_GEN(i915) >= 5 && intel_has_gpu_reset(i915))
>> +       if (INTEL_GEN(i915) >= 5 && intel_has_gpu_reset(i915)) {
>> +               intel_uc_prepare_to_reset(i915);
>>                  WARN_ON(intel_gpu_reset(i915, ALL_ENGINES));
> This still feels wrong. If we accept that we will have to reload the fw
> on resume, why are we not just sanitzing the uc state and forcing the
> reload?
Hi Chris,

intel_uc_prepare_to_reset() is sanitizing uc state and reload is 
happening through gem_init_hw in resume path.
what are we missing?

Thanks,
Sagar
> -Chris

-- 
Thanks,
Sagar