> -----Original Message----- > From: Christian König [mailto:deathsimple@xxxxxxxxxxx] > Sent: Wednesday, February 18, 2015 7:02 AM > To: Ross Zwisler; Deucher, Alexander > Cc: Michel Dänzer; linux-kernel@xxxxxxxxxxxxxxx; dri- > devel@xxxxxxxxxxxxxxxxxxxxx; Dave Airlie; Lauri Kasanen; Koenig, Christian > Subject: Re: [PATCH] drm/radeon: Fix regression with suspend/resume > > On 17.02.2015 18:49, Ross Zwisler wrote: > > On Sat, 2015-02-14 at 06:25 +0000, Deucher, Alexander wrote: > >>> -----Original Message----- > >>> From: Ross Zwisler [mailto:ross.zwisler@xxxxxxxxxxxxxxx] > >>> Sent: Friday, February 13, 2015 10:55 PM > >>> To: Michel Dänzer > >>> Cc: linux-kernel@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > Deucher, > >>> Alexander; Dave Airlie; Lauri Kasanen; Koenig, Christian > >>> Subject: Re: [PATCH] drm/radeon: Fix regression with suspend/resume > >>> > >>> On Fri, 2015-02-13 at 11:41 +0900, Michel Dänzer wrote: > >>>> On 13.02.2015 05:30, Ross Zwisler wrote: > >>>>> This patch reverts the changes made in this commit: > >>>>> > >>>>> deadcb36f49b ("drm/radeon: Use two-ended allocation by size, v2") > >>>>> > >>>>> That patch caused a regression on my system where the bottom of > the > >>>>> screen flickers after my laptop goes thorough a suspend and resume. > >>>> What kind of flicker is it? E.g. does it only affect X or also console, > >>>> does it flicker all the time or only when there is activity, what does > >>>> it look like, ... > >>> It's kind of hard to describe it precisely, so I made a video. :) > >>> > >>> http://youtu.be/ESm9SMnr0do > >>> > >>> It only affects X, not the console, and it seems to go away if you log > >>> out back to the login manager (I'm using GDM on Fedora 20) and back > into > >>> your window manager. > >> Does a VT switch or forcing a dpms cycle (sleep 5; xset dpms force off) > >> also fix it? It doesn't look related to the patch in question at all. > >> Is the flickering 100% reproducible or does it only happen > >> periodically? > > From kernels 3.14 or so (when the deadcb36f49b patch was introduced) > > till 3.18 it happened 100% of the time. With 3.19 it only seems to > > happen maybe 50% of the time, but is still very easily reproducible. > > Well, what the patch does is just changing where buffers are placed in > memory. E.g. now we place the buffer at the end of memory as well. > > So I can imagine at least three possible causes for the issues you see: > 1. We haven't implemented all buffer placement restrictions correctly > and without the patch everything just works fine by coincident. > 2. Something is overwriting the buffer at it's new location. > @Alex&Michel: Didn't we had a similar problem internally recently? Or > was that just for APUs? I think that was just two engines trying to use the same memory location for writeback since we had not properly allocated a writeback slot. What's odd to me is that the region is actively flickering, it looks almost like a display timing issue. I would expect static corruption unless something else is actively writing to the region. Alex > 3. One of the memory chips on your hardware is faulty and without the > patch the we just don't use the affected region (rather unlikely). > > For testing could you try to limit the amount of VRAM used? E.g. give > radeon.vramlimit=256 as kernel commandline to limit the VRAM to the > first 256MB. > > Regards, > Christian. > > > > > It's entirely possible that the patch isn't the root cause, but it just > > brought out a bug somewhere else. All I know is that I did a bisect, > > and with the commit before this the issue never happens, and after this > > commit it happens 100% of the time. :) Also, reverting that commit with > > 3.19 makes the issue go away. > > > > Nope, "xset dpms force off" doesn't fix it. After the screen goes black > > and comes back, the flicker is still there. > > > > - Ross > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > http://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
