[Mesa-dev] gallium: blitters and scissors

[Dave Airlie]

On Wed, Oct 13, 2010 at 1:07 PM, Dave Airlie <airlied at gmail.com> wrote:
> On Wed, Oct 13, 2010 at 12:07 PM, Dave Airlie <airlied at gmail.com> wrote:
>> I've noticed that none of the blitters use scissor state, and wondered
>> if there was a reason for this.
>>
>> It looks like drivers are expected to setup scissor state in the
>> framebuffer setup and in the set scissor state, but with r600g due to
>> the underlying state tracking it can end up doing the wrong thing.
>>
>> The 3 patches add CSO cache + u_blit + u_blitter scissor usage.
>>
>> Just wondering if I'm violating some rules of the gallium interface or not.
>
> I realised this was a quite deep hole I started digging in mesa/st,
> any advice on whether cleaning it up is a good idea?
>

Okay so it helps to read the docs, since it the scissor state enable
relies on a bit in the rasterizer state.

So it looks like we should always set scissor regs in the framebuffer
state and only modify them if we notice
the rasterizer bit is enabled.

Dave.