[Mesa-dev] [PATCH 22/20] radeonsi: disable early Z if the fragment shader writes to memory

[Nicolai Hähnle]

On 19.03.2016 17:55, Marek Olšák wrote:
> I made comments on patches 17 & 18.
>
> With those addressed, patches 13-22 including 15 v2 are:
>
> Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Thanks. I'll just make sure that all the LLVM requirements are also 
committed upstream and then I'll push this series.

Cheers,
Nicolai

> Marek
>
> On Wed, Mar 16, 2016 at 4:09 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
>> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>>
>> Empirically, both the EXEC_ON_* flags and LATE_Z are necessary.
>> ---
>>   src/gallium/drivers/radeonsi/si_state_shaders.c | 14 ++++++++++++--
>>   1 file changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
>> index 5fe1f79..7251092 100644
>> --- a/src/gallium/drivers/radeonsi/si_state_shaders.c
>> +++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
>> @@ -794,9 +794,15 @@ static void si_shader_ps(struct si_shader *shader)
>>           * - the shader uses at least 2 VMEM instructions, or
>>           * - the code size is at least 50 2-dword instructions or 100 1-dword
>>           *   instructions.
>> +        *
>> +        * Shaders with side effects that must execute independently of the
>> +        * depth test require LATE_Z.
>>           */
>> -       if (info->num_memory_instructions >= 2 ||
>> -           shader->binary.code_size > 100*4)
>> +       if (info->writes_memory &&
>> +           !info->properties[TGSI_PROPERTY_FS_EARLY_DEPTH_STENCIL])
>> +               shader->z_order = V_02880C_LATE_Z;
>> +       else if (info->num_memory_instructions >= 2 ||
>> +                shader->binary.code_size > 100*4)
>>                  shader->z_order = V_02880C_EARLY_Z_THEN_RE_Z;
>>          else
>>                  shader->z_order = V_02880C_EARLY_Z_THEN_LATE_Z;
>> @@ -1157,6 +1163,10 @@ static void *si_create_shader_selector(struct pipe_context *ctx,
>>          if (sel->info.properties[TGSI_PROPERTY_FS_EARLY_DEPTH_STENCIL])
>>                  sel->db_shader_control |= S_02880C_DEPTH_BEFORE_SHADER(1);
>>
>> +       if (sel->info.writes_memory)
>> +               sel->db_shader_control |= S_02880C_EXEC_ON_HIER_FAIL(1) |
>> +                                         S_02880C_EXEC_ON_NOOP(1);
>> +
>>          /* Compile the main shader part for use with a prolog and/or epilog. */
>>          if (sel->type != PIPE_SHADER_GEOMETRY &&
>>              !sscreen->use_monolithic_shaders) {
>> --
>> 2.5.0
>>
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