[Intel-gfx] [PATCH v4 8/9] drm/i915/perf: Add engine class instance parameters to perf

[Umesh Nerlige Ramappa]

On Tue, Mar 07, 2023 at 05:45:48PM -0800, Dixit, Ashutosh wrote:
>On Tue, 07 Mar 2023 12:16:10 -0800, Umesh Nerlige Ramappa wrote:
>>
>
>Hi Umesh,
>
>> +	/* Defaults when class:instance is not passed */
>> +	class = I915_ENGINE_CLASS_RENDER;
>> +	instance = 0;
>> +
>>	for (i = 0; i < n_props; i++) {
>>		u64 oa_period, oa_freq_hz;
>>		u64 id, value;
>> @@ -4174,7 +4156,13 @@ static int read_properties_unlocked(struct i915_perf *perf,
>>			}
>>			props->poll_oa_period = value;
>>			break;
>> -		case DRM_I915_PERF_PROP_MAX:
>> +		case DRM_I915_PERF_PROP_OA_ENGINE_CLASS:
>> +			class = (u8)value;
>> +			break;
>> +		case DRM_I915_PERF_PROP_OA_ENGINE_INSTANCE:
>> +			instance = (u8)value;
>> +			break;
>
>I am wondering since this is uapi we should make it robust. So if the user
>passes either class or instance he must pass both and we should check for
>that. If only one is passed we should not implicitly assume the other as we
>are doing here (if only instance is passed here we will assume RCS and if
>only class is passed we will assume instance 0). I think making this
>explicit will avoid confusion later. Thoughts?

Agree. We should only allow this configuration as a pair.

Thanks,
Umesh