[PATCH 2/2] drm/i915: properly clflush pwrites to phys objects
daniel at ffwll.ch
Tue Nov 29 08:16:52 PST 2011
On Tue, Nov 29, 2011 at 03:35:54PM +0000, Chris Wilson wrote:
> On Tue, 29 Nov 2011 16:09:29 +0100, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > Usually results in (rare) cursor corruptions on platforms
> > requiring physically addressed cursors.
> So the phys cursor pages are set to WC upon creation, are we just
> missing the mb()? Or more likely the CPUs don't have PAT and we are
> being lazy in not detecting the error.
Yes, on reconsidering the tested-by is from a pentium m, which has working
pat, and we do a wbinvd in the i8xx chipset flush, so I don't know anymore
how this patch actually works.
But it seems to indeed fix the issue for at least one reporter and cursor
update is about as far away from a perf critical path as possible, so who
cares about such minor quibbles, it works ;-)
Mail: daniel at ffwll.ch
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