[Mesa-dev] Status of VDPAU and XvMC state-trackers (was Re: Build error on current xvmc-r600 pipe-video)

[Alex Deucher]

2011/4/26 Christian König <deathsimple at vodafone.de>:
> Hi Alex,
>
> Am Dienstag, den 26.04.2011, 09:52 -0400 schrieb Alex Deucher:
>> This looks great Christian.  Nice work.  One quick note regarding
>> 68cc6bc5d8b6986acc7f5780d705f4ae9be2a446, COLOR[0-7]_INFO does need a
>> bo.  It's required since that reg has the tiling field and we need the
>> reloc to know if the surface is tiled or not.
>
> Ah, thanks for that. I was really wondering why this register was market
> with this flag, because it contains neither addr nor length of a block.
>
> But one question remains: What's the correct way to fix that?
>
> Hacking the winsys code to do the relocation only when a bo is specified
> is easy, but I'm not really sure what the drm cb checker will say to
> that. Ok, I just implemented this while typing and it seems to work fine
> (at least on kernel 2.6.37).
>
> Another open end I wanted to ask you is about this diff fragment from
> r600_state.c:
>
>        /* on R600 this can't be set if BLEND_CLAMP isn't set,
>           if BLEND_FLOAT32 is set of > 11 bits in a UNORM or SNORM */
> -       if (desc->colorspace != UTIL_FORMAT_COLORSPACE_ZS &&
> -           desc->channel[i].size < 12)
> +       if (desc->colorspace != UTIL_FORMAT_COLORSPACE_ZS && desc->channel[i].size < 12) {
> +               //TODO: Seems to work on RV710, but i have no idea what to do between R600-RV710
> +               if (rctx->family < CHIP_RV710) {
> +                       color_info |= S_0280A0_BLEND_CLAMP(1);
> +                       color_info_mask |= S_0280A0_BLEND_CLAMP(1);
> +               }
>                color_info |= S_0280A0_SOURCE_FORMAT(V_0280A0_EXPORT_NORM);
> +       }
>
> According to the documentation and comments BLEND_CLAMP seems to be
> necessary on R600 with 8bit snorm buffers, but this implies that we
> would never be able to fully implement the clamping control from
> ARB_color_buffer_float spec...
>
> Tests on my RV710 are showing that 8bit snorm buffers are still working
> quite fine even without BLEND_CLAMP, so what does R600 means in this
> case? R6xx, but not R7xx chipset family? or just the original R600
> chipset?

Setting SOURCE_FORMAT to EXPORT_NORM (1) is merely an optimization.
Leaving SOURCE_FORMAT at 0 will work in all cases, but is less
efficient.  The conditions for the setting the SOURCE_FORMAT=1
optimization are as follows:

R600/RV6xx:
BLEND_CLAMP is enabled
BLEND_FLOAT32 is disabled
11-bit or smaller UNORM/SNORM/SRGB

R7xx:
11-bit or smaller UNORM/SNORM/SRGB
16-bit or smaller FLOAT

Also, note that the following fields in CB_COLOR[0-7]_INFO are gone in r7xx:
READ_SIZE, CLEAR_COLOR, BLEND_FLOAT32, and TILE_COMPACT.

Alex

>
> Regards,
> Christian.
>
>