[Mesa-dev] gallium and ARB_texture_query_levels

[Ilia Mirkin]

On Mon, Feb 24, 2014 at 3:38 AM, Dave Airlie <airlied at gmail.com> wrote:
> I've taken a quick look at ARB_texture_query_levels,
>
> and the HW generally seems to implement this by returning it in the W
> channel of RESINFO, which would map to the TXQ instruction,
>
> So my initial implementation added a LEVQ TGSI instruction but I do
> think this isn't representative of the hw and I should add it to TXQ
> with maybe a CAP to say it supports levels.

Is there even hw that supports TXQ but doesn't return the levels info
in W? A quick grep suggests that llvmpipe, ilo, nv50+, r600+ support
TXQ. I assume that llvmpipe shouldn't be an issue, nv50+ has it, and I
believe you've indicated that r600+ has it. So the question is whether
ilo can do it or not... looking at the i965 code, it seems like ir_txs
and ir_query_levels are handled with the same shader opcode. And
there's a comment "/* # levels is in .w */"...

  -ilia