[Mesa-dev] [PATCH 1/9] gallium: Add PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY

[Ilia Mirkin]

On Mon, Jan 18, 2016 at 6:52 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
>
>
> On 18.01.2016 18:50, Ilia Mirkin wrote:
>>
>> On Mon, Jan 18, 2016 at 5:22 PM, Nicolai Hähnle <nhaehnle at gmail.com>
>> wrote:
>>>
>>> diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>>> b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>>> index 933330f..1ae557d 100644
>>> --- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>>> +++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>>> @@ -75,6 +75,8 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum
>>> pipe_cap param)
>>>         return 1;
>>>      case PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE:
>>>         return 2048;
>>> +   case PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY:
>>> +      return 0;
>>>      /* supported capabilities */
>>>      case PIPE_CAP_TWO_SIDED_STENCIL:
>>>      case PIPE_CAP_ANISOTROPIC_FILTER:
>>> diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> index 712835c..99d7ae6 100644
>>> --- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> +++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>>> @@ -121,6 +121,8 @@ nv50_screen_get_param(struct pipe_screen *pscreen,
>>> enum pipe_cap param)
>>>         return 256;
>>>      case PIPE_CAP_TEXTURE_BUFFER_OFFSET_ALIGNMENT:
>>>         return 1; /* 256 for binding as RT, but that's not possible in GL
>>> */
>>> +   case PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY:
>>> +      return 0;
>>>      case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
>>>         return NOUVEAU_MIN_BUFFER_MAP_ALIGN;
>>>      case PIPE_CAP_MAX_VIEWPORTS:
>>> diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>>> b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>>> index 7211df9..612f1c0 100644
>>> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>>> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>>> @@ -111,6 +111,8 @@ nvc0_screen_get_param(struct pipe_screen *pscreen,
>>> enum pipe_cap param)
>>>         return 256;
>>>      case PIPE_CAP_TEXTURE_BUFFER_OFFSET_ALIGNMENT:
>>>         return 1; /* 256 for binding as RT, but that's not possible in GL
>>> */
>>> +   case PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY:
>>> +      return 0;
>>>      case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
>>>         return NOUVEAU_MIN_BUFFER_MAP_ALIGN;
>>>      case PIPE_CAP_MAX_VIEWPORTS:
>>
>>
>> I would greatly appreciate it if you could stick these into the
>> "unsupported" list of caps -- each of nv30/nv50/nvc0 should have one,
>> of varying length. (Same applies to the other cap you're adding.)
>
>
> Do you really want that? I actually put them aside on purpose, because the
> somewhat unusual sense of the cap means that the return value of 1 is
> something unsupported. Of course, one might argue that I should have changed
> the boolean sense and renamed it to something like
> PIPE_CAP_BUFFER_SAMPLER_VIEW_SWIZZLES.

Oh I see. Yes, that is somewhat odd. Most caps return 0 for
unsupported and 1 for supported. I have a mild preference to flipping
the meaning, but wait to see if others have similar feedback before
doing the work of flipping it. But ultimately you could argue that
there's a highly sought-after capability of "rgba only" and nouveau
doesn't support it :) I think I'd still prefer to see it in the
unsupported list if you don't mind. (Or in the supported list if you
should flip the meaning.)

  -ilia