[Mesa-dev] [PATCH] nv50: report only 16 texure_samplers

[Emil Velikov]

On 12/10/13 01:25, Roland Scheidegger wrote:
> Am 12.10.2013 02:02, schrieb Brian Paul:
>> On 10/11/2013 10:44 AM, Emil Velikov wrote:
>>> Current mesa code(cso and drivers) expect and use only up-to 16
>>> texture samplers.
>>>
>>> Verbatum copy from the nvc0 driver.
>>>
>>> Cc "9.1" <mesa-stable at lists.freedesktop.org>
>>> Cc "9.2" <mesa-stable at lists.freedesktop.org>
>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70212
>>> Reported-by: Aaron Watry <awatry at gmail.com>
>>> Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
>>> ---
>>>   src/gallium/drivers/nouveau/nv50/nv50_screen.c | 4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>> diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> index f454ec7..3f81cc4 100644
>>> --- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> +++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> @@ -249,7 +249,11 @@ nv50_screen_get_shader_param(struct pipe_screen
>>> *pscreen, unsigned shader,
>>>      case PIPE_SHADER_CAP_INTEGERS:
>>>         return 1;
>>>      case PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS:
>>> +      return 16; /* would be 32 in linked (OpenGL-style) mode */
>>> +      /*
>>> +   case PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLER_VIEWS:
>>>         return 32;
>>> +      */
>>>      default:
>>>         NOUVEAU_ERR("unknown PIPE_SHADER_CAP %d\n", param);
>>>         return 0;
>>>
>>
>> Since PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLER_VIEWS doesn't really exist,
>> I'd rather see it removed entirely.
> Actually it doesn't seem to exist at all?
> 
Indeed and afaics it never did :)

As the commit says it's a verbatim copy of nvc0, which also started with
32 TEXTURE_SAMPLERS.

>> If you wanted to future-proof the code you could do
>>    return MIN2(32, PIPE_MAX_SAMPLERS);
>>
>> in case we bump PIPE_MAX_SAMPLERS to 32 one of these days.
>>
>>
>> In any case, Reviewed-by: Brian Paul <brianp at vmware.com>
>>
> 
> 
> Well I think there is quite some hw out there which can only do 16
> samplers but more sampler views as this is what d3d10/11 wants (16
> samplers max per stage, but 128 sampler views). So making it queryable
> may have some benefits, but OpenGL can't really make any use of it in
> any case.
> 
I'm not entirely sure what is the case in here, as I'm a bit short of
knowledge about the hardware, especially with the lack of documentation.

FWIW I've intentionally added/copied the SAMPLER_VIEWS, as I feel it's
beneficial in the long term. That is after going through the build
system(s), my plan is to jump into the nv50 driver + vdpau st and some
of the missing extensions and other things along the way :)

Cheers
Emil

> Roland
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>