https://bugzilla.kernel.org/show_bug.cgi?id=58121
Summary: Radeon SUMO: LVDS panel blanks when enabling external monitor Product: Drivers Version: 2.5 Kernel Version: 3.9 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: niels_ole@salscheider-online.de Regression: No
Created an attachment (id=101411) --> (https://bugzilla.kernel.org/attachment.cgi?id=101411) dmesg with drm.debug=4
When I enable both my LVDS panel and an external monitor (e.g. DP or VGA), my LVDS panel blanks. This is on a radeon SUMO GPU (AMD A6-3410MX APU). I have attached the dmesg output with drm.debug=4 and my Xorg.0.log.
https://bugzilla.kernel.org/show_bug.cgi?id=58121
--- Comment #1 from Niels Ole Salscheider niels_ole@salscheider-online.de 2013-05-14 10:23:54 --- Created an attachment (id=101421) --> (https://bugzilla.kernel.org/attachment.cgi?id=101421) Xorg.0.log
https://bugzilla.kernel.org/show_bug.cgi?id=58121
Alex Deucher alexdeucher@gmail.com changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |alexdeucher@gmail.com
--- Comment #2 from Alex Deucher alexdeucher@gmail.com 2013-05-14 12:42:31 --- Is this a regression?
https://bugzilla.kernel.org/show_bug.cgi?id=58121
--- Comment #3 from Niels Ole Salscheider niels_ole@salscheider-online.de 2013-05-14 20:22:53 --- I thought so at first since I believe that I tested multihead after implementing 0a9069d34918659bc8a89e21e69e60b2b83291a3.
But now it does not work with older kernel versions, either.
https://bugzilla.kernel.org/show_bug.cgi?id=58121
黄家垚 huangjiayao_1992@163.com changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |huangjiayao_1992@163.com
--- Comment #4 from 黄家垚 huangjiayao_1992@163.com --- This also appeared on my laptop(A6 3400M and A8 3500M) with Linux 3.5.0 to 3.11. For using external monitor, i can only use Linux 3.4.x. I an looking forward to use newer Linux kernel on my laptop.
https://bugzilla.kernel.org/show_bug.cgi?id=58121
Alan alan@lxorguk.ukuu.org.uk changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |alan@lxorguk.ukuu.org.uk Kernel Version|3.9 |3.11
https://bugzilla.kernel.org/show_bug.cgi?id=58121
--- Comment #5 from Alex Deucher alexdeucher@gmail.com --- (In reply to 黄家垚 from comment #4)
This also appeared on my laptop(A6 3400M and A8 3500M) with Linux 3.5.0 to 3.11. For using external monitor, i can only use Linux 3.4.x. I an looking forward to use newer Linux kernel on my laptop.
Can you bisect?
https://bugzilla.kernel.org/show_bug.cgi?id=58121
Niels Ole Salscheider niels_ole@salscheider-online.de changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |niels_ole@salscheider-onlin | |e.de
--- Comment #6 from Niels Ole Salscheider niels_ole@salscheider-online.de --- Created attachment 127381 --> https://bugzilla.kernel.org/attachment.cgi?id=127381&action=edit Possible fix
I tried a current git checkout and noticed that now only DisplayPort monitors cause the problem - VGA works fine. After debugging the issue a bit further I noticed that the problem seems to be caused by a shared PLL between the bridge chip and the DP monitor.
The attached patch fixes the issue for me but I am not sure if we must not share PLLs at all or just not with the bridge chip.
https://bugzilla.kernel.org/show_bug.cgi?id=58121
Niels Ole Salscheider niels_ole@salscheider-online.de changed:
What |Removed |Added ---------------------------------------------------------------------------- Kernel Version|3.11 |3.14
https://bugzilla.kernel.org/show_bug.cgi?id=58121
--- Comment #7 from Alex Deucher alexdeucher@gmail.com --- Created attachment 127441 --> https://bugzilla.kernel.org/attachment.cgi?id=127441&action=edit updated version of the patch
The patch looks good. We already disable PLL sharing for non-DP displays, so we should also disable it for DP displays as well. DCE4.1 only supports 2 displays anyway so sharing doesn't really buy us much. I updated the patch slightly to make the logic a little cleaner. I'll add it to my -fixes queue.
dri-devel@lists.freedesktop.org
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