[Intel-gfx] [PATCH 3/4] drm/i915: opt-out CPU and WC mmaps from FBC

chris at chris-wilson.co.uk chris at chris-wilson.co.uk
Fri Mar 25 14:17:17 UTC 2016

On Fri, Mar 25, 2016 at 02:05:42PM +0000, Zanoni, Paulo R wrote:
> What if I have both a WC mmap and a GTT mmap, and I'm actually using
> the GTT mmap now? My set_domain call will be treated as WC mmap usage,
> while in fact it should be treated as GTT usage. Is there a way to
> differentiate between them with the current set_domain API?

No, there is not. As far as the cache domain is regarded WC/GTT appear to
be identical, i.e. GTT is just WC. That the GTT is not as coherent as
previously regarded is yet another bug.

Chris Wilson, Intel Open Source Technology Centre

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