[Mesa-dev] [PATCH 1/7] ac/surface: handle DCC subresource fast clear restriction on VI

[Bas Nieuwenhuizen]

On Wed, Apr 18, 2018 at 2:11 PM, Marek Olšák <maraeo at gmail.com> wrote:
> On Wed, Apr 18, 2018 at 4:44 PM, Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> wrote:
>>
>> IIRC if level N is unaligned then num_dcc_levels <= N+1, so level N+1
>> is not DCC compressed?
>
>
> There is a difference between being aligned (contiguous really) and being
> compressible. Small mip levels might be unaligned but may still
> compressible. Non-contiguous can mean that DCC of multiple mip levels is
> interleaved in memory. It can't be cleared with memset trivially, but it can
> still be compressed.

Hw-wise probably, but if level N is not aligned addrlib will set
subLvlCompressible to false[1], and hence the next level will not be
DCC compressed[2]?

[1] https://cgit.freedesktop.org/mesa/mesa/tree/src/amd/addrlib/r800/ciaddrlib.cpp#n268
[2] https://cgit.freedesktop.org/mesa/mesa/tree/src/amd/common/ac_surface.c#n345

>
> Marek
>