[Intel-gfx] [PATCH 5/7] drm/i915: Expose RPCS (SSEU) configuration to userspace (Gen11 only)
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Dec 31 15:39:54 UTC 2018
On 31/12/2018 15:33, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-12-31 15:21:15)
>>
>> On 14/12/2018 13:33, Chris Wilson wrote:
>>> Quoting Tvrtko Ursulin (2018-12-14 12:34:47)
>>>> +static int get_sseu(struct i915_gem_context *ctx,
>>>> + struct drm_i915_gem_context_param *args)
>>>> +{
>>>> + struct drm_i915_gem_context_param_sseu user_sseu;
>>>> + struct intel_engine_cs *engine;
>>>> + struct intel_context *ce;
>>>> + int ret;
>>>> +
>>>> + if (args->size == 0)
>>>> + goto out;
>>>> + else if (args->size < sizeof(user_sseu))
>>>> + return -EINVAL;
>>>> +
>>>> + if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
>>>> + sizeof(user_sseu)))
>>>> + return -EFAULT;
>>>> +
>>>> + if (user_sseu.rsvd1 || user_sseu.rsvd2)
>>>> + return -EINVAL;
>>>
>>> I'd vote for s/rsvd2/flags/ straight away as already I can suggest we
>>> allow for USE_CTX_ENGINE to swap class/instance for engine-id so that we
>>> can set rpcs for, and not least, a virtual engine.
>>
>> Hm.. would it be useful? It would just be a way of indirection.
>>
>> engines = [vcs:0, vcs:1]
>> ctx.set_map(engines)
>>
>> And then a):
>>
>> foreach engine in engines:
>> ctx.set_sseu(engine, flags=0)
>>
>> vs b):
>>
>> for i = 0; i < len(engines); i++:
>> ctx.set_sseu(i, flags=USE_CTX_ENGINE)
>>
>> So I don't see any benefit. But maybe I missed your idea.
>
> The virtual engine doesn't have a valid class:instance, only its index
> in the per-context engines[]. And we want to control its context image,
> not the context images on each of the real engine.
True. At first I was thinking that it is equivalent to setting SSEU to
all engines from the map but of course we only have one context image..
Okay, I will rename this to flags straight away.
Regards,
Tvrtko
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