[Intel-gfx] [PATCH] drm/i915/GuC: Combine the two kernel parameter into one

[Tvrtko Ursulin]

[corrected my email in cc]

On 12/11/2016 02:21, Jeff McGee wrote:
> On Wed, Nov 09, 2016 at 11:11:07AM -0800, Anusha Srivatsa wrote:
>> Replace i915.enable_guc_loading and i915.enable_guc_submission
>> with a single parameter - i915.enable_guc. Where:
>>
>> -1 : Platform default (Only load GuC)
>> 0 : Do not use GuC
>> 1 : Load GuC, do not use Command Submission through GuC
>> 2 : Load and use GuC for Command Submission
>>
> I think this approach could get ugly as we add more GuC functionality and
> the list of combinations under this one parameter grows.
>
> What is the issue we are trying to solve? I thought it was that folks
> didn't like that we had an option to just load GuC and do nothing with it.
> Can those folks please comment?

I am not one of those folks but I also am sure about the proposed 
change. Same concern about extensibility and also usability.

What is the difference between -1 and 1 for example? Is 1 equivalent to 
the current "must use" (2) option? And -1 is equivalent to the current 
"try to use" (1)?

Then you got proposed 2 (load and use guc) but that does not capture the 
option for built-in GuC firmware Dave has planned for in his version. I 
don't know if that is real or not, just saying

I am also not sure it is so imperative to change this at all. But if 
people do want to change it we should make it really good. :)

One idea could be to hide the guc loading form the user altogether and 
hence improve usability (decrease exposed complexity) by having only two 
parameters; i915.enable_guc_scheduling and i915.enable_huc.

Whether or not firmware would be loaded would depend on if either of the 
two is turned on. That would also preserve the option of current 
fallback or wedge behaviour for guc.

Regards,

Tvrtko