Created attachment 113508 [details]
journalctl -b | grep "\[drm"
I am running Arch Linux on an AMD A6-3500 with Radeon HD 6530D graphics on an Gigabyte A55M-S2V mainboard. I just received updated X server to version 1.17.1 together with a rebuilt version 7.5.0 of the XFree86 ATI driver with the kernel staying at 3.18.6.
I do have two Samsung monitors connected to the system, one via DVI and one via VGA. This setup always initialized unreliably and I had to manually add modes for the VGA-connected monitor using
xrandr --newmode "1680x1050_60.00" 146.25 1680 1784 1960 2240 1050 1053 1059 1089 -hsync +vsync
xrandr --addmode VGA-0 "1680x1050_60.00"
xrandr --output VGA-0 --mode "1680x1050_60.00"
for it to work at all. But after the update described above, the two monitors never initialize properly anymore. Before the update, I sometimes had to power-cycle (meaning switch off power not just a reboot) but it did eventually work after two or three tries.
The reason I am reporting this as a Radeon DRM issue instead of an X server problem is that my system log contains errors from the DRM driver about "channel eq" and "clock recovery". I attached those logs grepped for "[drm".
Thank for your help and please tell me if I can provide any further information to help diagnose this.
Created attachment 113509 [details]
journalctl -b | grep "\[drm"
Maybe as a clarification: Both monitors always initialize properly when only one is connected.
(In reply to Adam Reichold from comment #2)
> Maybe as a clarification: Both monitors always initialize properly when only
> one is connected.
When only one is connected at boot time? If so does it matter which one?
(In reply to Alex Deucher from comment #3)
> (In reply to Adam Reichold from comment #2)
> > Maybe as a clarification: Both monitors always initialize properly when only
> > one is connected.
> When only one is connected at boot time? If so does it matter which one?
If at boot time, only one monitor is connected, then it does initialize properly. This is true for both monitors, i.e. VGA-only works and DVI-only works, but not both at the same time. (It also works correctly if I boot using only one monitor and attach the second one later.)
I had some more time to test this (now on kernel 4.1.4 and X server 1.17.2) and have made two hopefully useful observations:
* The Catalyst driver (version 15.7) is always able to initialize the setup even though VGA-connected monitor seems to always "flicker" two times before reaching the final mode.
* I have found a somewhat reliable workaround to use with the free driver: By adding
xrandr --output VGA-0 --off
--output VGA-0 --preferred --primary \
--output DVI-0 --preferred --rotate left --right-of VGA-0
to my .xinitrc, the system will properly initialize both displays even though the first command seems to take around two seconds to complete.
Maybe of interest w.r.t this: Running kernel 4.3.3. by now, I found a seemingly reliable workaround, i.e. if the VGA-connected monitor does not initialize after boot, it will always properly initialize when I put the system into suspend-to-memory and wake it up again immediately after that. (But the VGA-connected monitor will sometimes go dark for a few seconds some time after it initialized for the first time.)
-- GitLab Migration Automatic Message --
This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.
You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/drm/amd/issues/583.