From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, stable@kernel.org
Subject: Re: [PATCH 2/2] drm/i915: properly clflush pwrites to phys objects
Date: Tue, 29 Nov 2011 17:16:52 +0100 [thread overview]
Message-ID: <20111129161652.GD5667@phenom.ffwll.local> (raw)
In-Reply-To: <c55c5d$185nps@AZSMGA002.ch.intel.com>
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@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 ;-)
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48
next prev parent reply other threads:[~2011-11-29 16:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-29 15:09 [PATCH 1/2] drm: add helper to clflush a virtual address range Daniel Vetter
2011-11-29 15:09 ` Daniel Vetter
2011-11-29 15:09 ` [PATCH 2/2] drm/i915: properly clflush pwrites to phys objects Daniel Vetter
2011-11-29 15:35 ` Chris Wilson
2011-11-29 15:35 ` Chris Wilson
2011-11-29 16:16 ` Daniel Vetter [this message]
2011-11-29 17:22 ` Daniel Vetter
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