On 27.04.2018 19:23, Marek Olšák wrote:
On Fri, Apr 27, 2018 at 4:14 AM, Nicolai Hähnle <nhaeh...@gmail.com
<mailto:nhaeh...@gmail.com>> wrote:
Sorry, but I still don't understand the logic of this :/
What we want to check for is that all the DCC bytes of a mip-level
are contiguous, right?
Why does it matter for that whether a level is the last level?
Here's the thought experiment that I can't make sense of: Let's say
that you have format, base level, and number of levels N so that the
last-level condition applies. That is, all levels up to and
including N-2 have dccRamAligned true. Level N-1 has dccRamAligned
false, but the patch as-is will still consider it fast-clearable.
Yes, because the non-contiguous level N-1 DCC range (last level) doesn't
overlap with any existing level. It's interleaved with level N that
doesn't exist. So clearing the level N-1 DCC range that might overwrite
level N DCC range doesn't break anything and so the clear is allowed.
Is it clear now?
Yes. I was thinking that dccFastClearSize is the number of bytes
belonging to the mip level that have to be cleared, but digging into
AddrLib it is in fact a span like you describe (which potentially
contains bytes that *don't* belong to the mip level). So the patch is
okay as-is.
Reviewed-by: Nicolai Hähnle <nicolai.haeh...@amd.com>
Marek
--
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.
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