Second monitor stopped working

[meleneemil]

Dear experts,
My setup is X1 Carbon, Linux Mint 20.1, lenovo docking station (usb-c), and two external displays:
- A Dell that always worked fine. Connected with displayport to docking station
- A Samsung, that has been going off since a while. Connected with displayport to docking station.

The problem: The one of the two external displays (the samsung one) stopped working again today. It has happened also in the past, but it was coming back after a reboot, I think.

Inxi SMCGx


xorg log


EDIT: Forgot to add:
I had 5.4.0-88 (LTS) when it happened.
Tried 5.11.0-37, but no change.
Still looking for the proper way to default back to 5.4. Managed to fix the grub timeout method, and now back on 5.4, and removed 5.11.

thank you in advance

[SMG]

The problem: The one of the two external displays (the samsung one) stopped working again today. It has happened also in the past, but it was coming back after a reboot, I think.

Cable connections can cause the "sometimes it works and sometimes it doesn't" issue and sometimes it just takes bumping the cable connection just a little to cause issues. I suggest checking to make sure all ends of the cables for the docking station and monitor in question are secure.

With your 8th-gen Intel, I would expect you would have less issues with the 5.11 kernel. While it might not "fix" this specific issue, you are running Intel graphics and the newer kernel would provide a newer driver.

Your Xorg log indicates you are running with a custom xorg.conf file. The log also seems to be missing the data I am used to seeing for a monitor with respect to the Samsung. There is no EDID info listed nor is there serial number/model info listed. That seems to indicate the monitor is not being recognized properly which might be why you are seeing the monitor "stopped working".

What type of info do you have in the custom xorg? Usually, most installs do not need a custom xorg.

[meleneemil]

thank you for the detailed response

The problem: The one of the two external displays (the samsung one) stopped working again today. It has happened also in the past, but it was coming back after a reboot, I think.

Cable connections can cause the "sometimes it works and sometimes it doesn't" issue and sometimes it just takes bumping the cable connection just a little to cause issues. I suggest checking to make sure all ends of the cables for the docking station and monitor in question are secure.

I had checked that but didn't find any suspicious connection. Connected it to another laptop for few days and there was no glitch. That said, I found it around the office, so maybe the chances of it being faulty are increasing, given your explanation.

With your 8th-gen Intel, I would expect you would have less issues with the 5.11 kernel. While it might not "fix" this specific issue, you are running Intel graphics and the newer kernel would provide a newer driver.

I'm still scared of kernel upgrades, and this last week didn't help. Normally, I would follow through, but this is now a work laptop, and I'd rather have the stability.

Your Xorg log indicates you are running with a custom xorg.conf file. The log also seems to be missing the data I am used to seeing for a monitor with respect to the Samsung. There is no EDID info listed nor is there serial number/model info listed. That seems to indicate the monitor is not being recognized properly which might be why you are seeing the monitor "stopped working".

What type of info do you have in the custom xorg? Usually, most installs do not need a custom xorg.

I tried several things the past year to make this laptop work with an eGPU, so possibly one of the leftovers is a custom xorg.conf.

How do you see that I have a custom xorg.conf?
I see the following lines mentioning the file, but not obvious to me that it's custom.

Code: Select all

[    16.053] (==) Using config file: "/etc/X11/xorg.conf"
[    16.053] (==) Using system config directory "/usr/share/X11/xorg.conf.d"

For context, I also use autorandr to easily swap between display configs (laptop+2 external monitors).

Please give me some pointers on the xorg.conf, so I can reply better to your question.

thanks again
Emil

[SMG]

I'm still scared of kernel upgrades, and this last week didn't help. Normally, I would follow through, but this is now a work laptop, and I'd rather have the stability.

I do not know the backstory to that comment, but reversing kernel upgrades are one of the easier tasks to accomplish if you decide you want to try it in the future.

I tried several things the past year to make this laptop work with an eGPU, so possibly one of the leftovers is a custom xorg.conf.

Usually eGPUs do require a custom xorg.

How do you see that I have a custom xorg.conf?
I see the following lines mentioning the file, but not obvious to me that it's custom.

Code: Select all

[    16.053] (==) Using config file: "/etc/X11/xorg.conf"
[    16.053] (==) Using system config directory "/usr/share/X11/xorg.conf.d"

Normally, there is only the second line (system config) and not the first line. The first one is the custom file.

You can try renaming the first file to xorg.conf.old and restarting X server with Ctl-Alt-Backspace to see if that makes a difference. (Note: You will lose anything you have open when you restart X Server. If you want, you can just rename the file and then check the next time you boot the computer to see if there is a difference.)

For context, I also use autorandr to easily swap between display configs (laptop+2 external monitors).

Unless there is something special set up in the profiles for autorandr, I would not think this is an issue. It's my understanding autorandr uses the info from X Server and the fact the Xorg log seems to be missing EDID info may be a key factor in this situation.

[shedyed]

The Dell was autodetected, but not the Samsung, after looking at the log file in your pastebin. How is the Dell connected though? Do you have a VGA cable for it? Try plugging the Samsung in its place, that is, let that screen take the Dell's place for this experiment. See if xrandr can provide information using xrandr -i on the command line. You should get signs of life, and two screens should work.

Share the results here, so we can proceed to the next step

Note to the moderators: Can we make a change to the working title of this issue. It's Third monitor stopped working. I'm browsing topics that are of interest to me, then I find out there's a mystery guest.

[SMG]

The Dell was autodetected, but not the Samsung, after looking at the log file in your pastebin. How is the Dell connected though?

The logfile indicates a DP connection, although that could be a function of the docking hardware and may not be correct.

Code: Select all

[    16.654] (II) modeset(0): EDID for output DP-1-2
[    16.654] (II) modeset(0): Manufacturer: DEL  Model: a07b  Serial#: xxxxxxx

Note to the moderators: Can we make a change to the working title of this issue. It's Third monitor stopped working. I'm browsing topics that are of interest to me, then I find out there's a mystery guest.

The OP of the thread can make a change if they desire. The computer is a laptop. It has one permanently attached screen and two external monitors attached through a docking station. One of those monitors stopped working. It would be unusual to refer to a laptop screen as a monitor because it can not be easily detached from the computer.