[Mesa-dev] Question about implementing viewport transfer and const load in nir

[Qiang Yu]

> btw, does lima have some way to write to memory from cmdstream (ie.
> without setting up a full blown draw)?  If so perhaps you could get
> away with leaving some extra space at the end of your uniform buffer
> that you copy driver internal uniforms into before kicking the draw?
Unfortunately lima can't do this. Seems you guys all know how to
"reserve space in uniform buffer", how?

>
> fwiw, freedreno does have driver specific uniforms, see
> ir3_driver_param.  Although normal uniforms (ie. non-UBO) get copied
> into internal memory, so I just upload driver specific uniforms (as
> needed) and immediates to the tail of the uniform memory before the
> draw.
So you mean freedreno will do an extra copy from the constant buffer
set by set_constant_buffer to a driver allocated memory then append
the driver spec uniform? If so, that can explain the trick above.

Regards,
Qiang