[Intel-gfx] [PATCH v3 4/5] drm/i915/guc: Add WOPCM partitioning support for CNL

[Yaodong Li]

On 12/08/2017 03:03 PM, Chris Wilson wrote:
> Quoting Jackie Li (2017-12-08 21:41:51)
>> +static inline int cnl_a0_wopcm_size_check(struct drm_i915_private *i915)
>> +{
>> +       struct intel_guc_wopcm *wopcm = &i915->guc.wopcm;
>> +       u32 huc_size = intel_uc_fw_get_size(&i915->huc.fw);
>> +
>> +       /*
>> +        * On CNL A0, hardware requires guc size to be larger than or equal to
>> +        * HuC kernel size.
>> +        */
> I couldn't find anything that told me that wopcm->size had to be greater
> than GEN10_GUC_WOPCM_OFFSET. Either that is always true by construction,
> in which case GEM_BUG_ON() here, or it may be too small in which case
> add the test.
It's a known HW limitation on CNL A0. And Yes, it should be unlikely to 
happen,
but once it happened, we only want to disable GuC loading and submission.
>> +       if ((wopcm->size - GEN10_GUC_WOPCM_OFFSET) < huc_size)
> ((((Do) you) like) brackets)?
Will Fix it. :-) Thanks!
> -Chris