From mboxrd@z Thu Jan 1 00:00:00 1970 From: lkml@pengaru.com Subject: BUG: 4.10 i915 drm display noise regression - bisected to a6a7cc4b7 Date: Mon, 9 Jan 2017 00:32:40 -0600 Message-ID: <20170109063240.GB9125@shells.gnugeneration.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel Cc: dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk List-Id: dri-devel@lists.freedesktop.org Hello all, I'm experiencing display noise in the form of 8x1 pixel bars spuriously appearing in random locations. This doesn't happen on 4.9, the machine is an X61s, a Core2Duo 1.8Ghz w/XGA via LVDS. I was able to bisect the issue to a6a7cc4b7: commit a6a7cc4b7db6deaeca11cdd38844ea147a354c7a Author: Chris Wilson Date: Fri Nov 18 21:17:46 2016 +0000 drm/i915: Always flush the dirty CPU cache when pinning the scanout Currently we only clflush the scanout if it is in the CPU domain. Also flush if we have a pending CPU clflush. We also want to treat the dirtyfb path similar, and flush any pending writes there as well. v2: Only send the fb flush message if flushing the dirt on flip v3: Make flush-for-flip and dirtyfb look more alike since they serve similar roles as end-of-frame marker. Reproduction is simple, just run this native drm eye candy program: https://github.com/vcaputo/rototiller Thanks, Vito Caputo