Re: [PATCH 47/47] drm/i915/guc: Unblock GuC submission on Gen11+

[Michal Wajdeczko]

On 02.07.2021 10:13, Martin Peres wrote:
> On 01/07/2021 21:24, Martin Peres wrote:
> [...]
>>>
>>>>
>>>>> +        i915->params.enable_guc = ENABLE_GUC_LOAD_HUC;
>>>>> +        return;
>>>>> +    }
>>>>> +
>>>>> +    /* Default: enable HuC authentication and GuC submission */
>>>>> +    i915->params.enable_guc = ENABLE_GUC_LOAD_HUC |
>>>>> ENABLE_GUC_SUBMISSION;
>>>>
>>>> This seems to be in contradiction with the GuC submission plan which
>>>> states:
>>>>
>>>> "Not enabled by default on any current platforms but can be enabled via
>>>> modparam enable_guc".
>>>>
>>>
>>> I don't believe any current platform gets this point where GuC
>>> submission would be enabled by default. The first would be ADL-P which
>>> isn't out yet.
>>
>> Isn't that exactly what the line above does?
> 
> In case you missed this crucial part of the review. Please answer the
> above question.

I guess there is some misunderstanding here, and I must admit I had
similar doubt, but if you look beyond patch diff and check function code
you will find that the very condition is:

        /* Don't enable GuC/HuC on pre-Gen12 */
        if (GRAPHICS_VER(i915) < 12) {
                i915->params.enable_guc = 0;
                return;
        }

so all pre-Gen12 platforms will continue to have GuC/HuC disabled.

Thanks,
Michal