[Mesa-dev] r6xx PIPE_CAP_MAX_RENDER_TARGETS

[Alex Deucher]

On Sun, Sep 25, 2011 at 7:09 AM, Benjamin Bellec <b.bellec at gmail.com> wrote:
> Hello,
>
> In src/gallium/drivers/r600/r600_pipe.c I saw this :
>
> /* Render targets. */
> case PIPE_CAP_MAX_RENDER_TARGETS:
>        /* FIXME some r6xx are buggy and can only do 4 */
>                return 8;
>
> The last line of R6xx_R7xx_3D.pdf says :
> 4 MRT + 8-Sample Restriction
> On RV610, there is a maximum of 4 enabled render targets for 8-sample
> surfaces.
>
> Is this related ?

Yes.

> I don't know what is 8-sample surfaces... so I don't know if the
> attached fix is as simple as this.
>

For most things you can use all 8 MRTs, the only case where you can is
when using 8 sample surfaces, so the code is correct as is for the
vast majority of cases.  It would probably be better to update the
comment to clarify that the 4 MRT limitation only applies in the 8
sample surface case and leave the MRTs at 8.

Alex

> Regards.
>
> Benjamin Bellec
>
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