[Mesa-dev] [PATCH v2 11/14] st/mesa: expose ARB_compute_variable_group_size

[Samuel Pitoiset]

On 09/12/2016 05:26 PM, Nicolai Hähnle wrote:
>
>
> On 11.09.2016 20:45, Samuel Pitoiset wrote:
>> This extension is only exposed if the underlying driver supports
>> ARB_compute_shader and if PIPE_COMPUTE_MAX_VARIABLE_THREADS_PER_BLOCK
>> is set.
>>
>> v2: - expose the ext based on that new cap
>>
>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>> ---
>>  src/mesa/state_tracker/st_extensions.c | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>>
>> diff --git a/src/mesa/state_tracker/st_extensions.c
>> b/src/mesa/state_tracker/st_extensions.c
>> index 807fbfb..ad7c637 100644
>> --- a/src/mesa/state_tracker/st_extensions.c
>> +++ b/src/mesa/state_tracker/st_extensions.c
>> @@ -1196,6 +1196,28 @@ void st_init_extensions(struct pipe_screen
>> *screen,
>>           extensions->ARB_compute_shader =
>>
>> extensions->ARB_shader_image_load_store &&
>>
>> extensions->ARB_shader_atomic_counters;
>> +
>> +         if (extensions->ARB_compute_shader) {
>> +            uint64_t max_variable_threads_per_block;
>> +
>> +            screen->get_compute_param(screen, PIPE_SHADER_IR_TGSI,
>> +
>> PIPE_COMPUTE_CAP_MAX_VARIABLE_THREADS_PER_BLOCK,
>> +                                      &max_variable_threads_per_block);
>
> I think this should check the return value. Or, in the earlier patch,
> the handling in sp_screen.c needs to be changed. Not sure what the
> convention should be, but as-is, using this with softpipe will not
> initialize max_variable_threads_per_block.

I think we never check the return value of get_compute_param(). But 
initializing max_variable_threads_per_block to 0 should actualy help, 
what do you think?

>
> Nicolai
>
>> +
>> +            for (i = 0; i < 3; i++) {
>> +               /* Clamp the values to avoid having a local work group
>> size
>> +                * greater than the maximum number of invocations.
>> +                */
>> +               consts->MaxComputeVariableGroupSize[i] =
>> +                  MIN2(consts->MaxComputeWorkGroupSize[i],
>> +                       max_variable_threads_per_block);
>> +            }
>> +            consts->MaxComputeVariableGroupInvocations =
>> +               max_variable_threads_per_block;
>> +
>> +            extensions->ARB_compute_variable_group_size =
>> +               max_variable_threads_per_block > 0;
>> +         }
>>        }
>>     }
>>
>>

-- 
-Samuel