[Mesa-dev] [PATCH 02/14] i965: Allocate binding table space for shader images.

[Francisco Jerez]

Kenneth Graunke <kenneth at whitecape.org> writes:

> On Friday, February 06, 2015 07:23:16 PM Francisco Jerez wrote:
>> Reviewed-by: Paul Berry <stereotype441 at gmail.com>
>> ---
>>  src/mesa/drivers/dri/i965/brw_context.h  | 5 +++++
>>  src/mesa/drivers/dri/i965/brw_shader.cpp | 7 +++++++
>>  2 files changed, 12 insertions(+)
>> 
>> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
>> index bebb0be..e28c65d 100644
>> --- a/src/mesa/drivers/dri/i965/brw_context.h
>> +++ b/src/mesa/drivers/dri/i965/brw_context.h
>> @@ -341,6 +341,7 @@ struct brw_stage_prog_data {
>>        uint32_t gather_texture_start;
>>        uint32_t ubo_start;
>>        uint32_t abo_start;
>> +      uint32_t image_start;
>>        uint32_t shader_time_start;
>>        /** @} */
>>     } binding_table;
>> @@ -621,6 +622,9 @@ struct brw_vs_prog_data {
>>  /** Max number of atomic counter buffer objects in a shader */
>>  #define BRW_MAX_ABO 16
>>  
>> +/** Max number of image units in a shader */
>> +#define BRW_MAX_IMAGES 16
>> +
>
> Out of curiosity, why 16?  The Windows driver and Nvidia both seem to
> use 8, while AMD offers 32:
>
> http://delphigl.de/glcapsviewer/gl_stats_caps_single.php?listreportsbycap=GL_MAX_IMAGE_UNITS
>
> We have 32 texture units on Haswell these days (though honestly, it's
> pretty arbitrary...we could have more if we wanted...)
>
> That's not an objection - I'm just curious.  As is,
> Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>
It's completely arbitrary too, IIRC I set it to 16 because back when I
wrote this patch we were still exposing 16 texture units, so I just used
the same value.  We could definitely expose 32 image units too, should I
just increase the value to 32 locally?

>>  /**
>>   * Max number of binding table entries used for stream output.
>>   *
>> @@ -653,6 +657,7 @@ struct brw_vs_prog_data {
>>                              BRW_MAX_TEX_UNIT * 2 + /* normal, gather */ \
>>                              12 + /* ubo */                              \
>>                              BRW_MAX_ABO +                               \
>> +                            BRW_MAX_IMAGES +                            \
>>                              2 /* shader time, pull constants */)
>>  
>>  #define SURF_INDEX_GEN6_SOL_BINDING(t) (t)
>> diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
>> index 67d8de4..5c8f3d5 100644
>> --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
>> +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
>> @@ -1116,6 +1116,13 @@ backend_visitor::assign_common_binding_table_offsets(uint32_t next_binding_table
>>        stage_prog_data->binding_table.abo_start = 0xd0d0d0d0;
>>     }
>>  
>> +   if (shader && shader->base.NumImages) {
>> +      stage_prog_data->binding_table.image_start = next_binding_table_offset;
>> +      next_binding_table_offset += shader->base.NumImages;
>> +   } else {
>> +      stage_prog_data->binding_table.image_start = 0xd0d0d0d0;
>> +   }
>> +
>>     /* This may or may not be used depending on how the compile goes. */
>>     stage_prog_data->binding_table.pull_constants_start = next_binding_table_offset;
>>     next_binding_table_offset++;
>> 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 212 bytes
Desc: not available
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20150207/f71b2d7e/attachment.sig>