Dear Maintainer,
Sometimes, during boot, the system will fail to initialize one of my monitors.
Whenever this problem occurs, it always impacts the same monitor. This monitor
is connected to the GPU via DisplayPort, while the other two monitors are
connected via DVI.
Then this problem occurs, I can see a message stating "link training failed"
for a short time, before the system continues the boot process by starting
lightdm. (Also, when the problem occurs, the GUI seems to be partially broken,
but I guess that is a bug in another package)
* What led up to the situation?
I powered on the computer and tried to boot Debian.
* What exactly did you do (or not do) that was effective (or ineffective)?
I didn't do anything except wait for something to show up on all three
monitors.
* What was the outcome of this action?
After a while, the second monitor that is connected via DVI turns on and
displays the same content as the primary DVI monitor. The DisplayPort monitor
stays black, displaying "No Signal".
After waiting a bit more, the display manager can be seen on both DVI monitors
(DP monitor is still black). The display manager seems to exhibit buggy
behaviour due to the failure to initialize the DP monitor.
* What outcome did you expect instead?
I expected the DP monitor to display the same information as the other two
monitors instead of staying black.
I attached the output of dmesg, captured after the problem occurred. It
contains this line:
[ 16.240502] nouveau 0000:01:00.0: disp: outp 05:0006:0f44: link training
failed
which led me to believe this is a bug in nouveau. If you think the bug is in
another package, please feel free to move this issue.
If you need additional information to debug this issue, please let me know.