From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 2/2] drm/i915: properly clflush pwrites to phys objects Date: Tue, 29 Nov 2011 17:16:52 +0100 Message-ID: <20111129161652.GD5667@phenom.ffwll.local> References: <1322579369-26954-1-git-send-email-daniel.vetter@ffwll.ch> <1322579369-26954-2-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Chris Wilson Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@kernel.org List-Id: dri-devel@lists.freedesktop.org On Tue, Nov 29, 2011 at 03:35:54PM +0000, Chris Wilson wrote: > On Tue, 29 Nov 2011 16:09:29 +0100, Daniel Vetter 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