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No external monitor on Ubuntu laptop

  • HardwareGeek

    Everything was working fine yesterday, until I rebooted for unrelated reasons. After rebooting, the laptop refuses to send any video to the HDMI port. In fact, AFAICT it doesn't even recognize that it has an HDMI port to send video to. (Although this is my first experience with Ubuntu, and I am not at all familiar with Ubuntu utilities or CLI tools for diagnosing such things.)

    Laptop: Lenovo ThinkPad X1 Carbon
    OS: Ubuntu 18.04.5 LTS
    Graphics: Intel HD Graphics 5500 (BDW TD2)
    Display manager: Gnome 3.28.2
    Monitor: LG 2560x1080 ultrawide

    Initially, the setup Just Worked. I think I may have had to set whether to duplicate or extend the laptop's display onto the external monitor, but I just plugged it in, and it got video.

    I have sudo access, but I don't really want to make any major changes to the configuration. It belongs to the client, and a significantly nonstandard configuration might be frowned upon.

    Any suggestions?

    1 Gąska 1 Reply
  • Gąska
    Banned

    @HardwareGeek said in No external monitor on Ubuntu laptop:

    monitor

    Ubuntu

    xrandr. The answer is always xrandr. Make a script with your config and put it in bashrc or whatever.

    1 HardwareGeek 1 Reply
  • HardwareGeek

    @Gąska I'm not quite sure what I'm doing with xrandr, but it reports HDMI-1 disconnected (normal left inverted right x axis y axis). Trying to tell it to do something with HDMI-1 doesn't seem to have any effect; it still says it's disconnected.

    Plugging the monitor into the DP jack works, sorta. I get output, but only 1920x1080, not 2560x1080, and xrandr says that HDMI-1 is connected, not DP-1. (Also, the laptop's built-in display is reported as eDP-1. I would assume the e means external, but apparently not, or else something is quite confused as to which display is which.) Edit: I can now use Ubuntu's GUI to position the displays to match the physical layout, and to change resolution, but not above 1920x1080. I still can't get the display's native resolution.

    1 Gąska 1 Reply
  • Gąska
    Banned

    @HardwareGeek said in No external monitor on Ubuntu laptop:

    @Gąska I'm not quite sure what I'm doing with xrandr, but it reports HDMI-1 disconnected (normal left inverted right x axis y axis). Trying to tell it to do something with HDMI-1 doesn't seem to have any effect; it still says it's disconnected.

    Plugging the monitor into the DP jack works, sorta. I get output, but only 1920x1080, not 2560x1080, and xrandr says that HDMI-1 is connected, not DP-1.

    Okay, there's something much more wrong with your setup than I initially thought. Can you check if booting from Live USB exhibits similar problems?

    Also, the laptop's built-in display is reported as eDP-1. I would assume the e means external

    Embedded.

    1 HardwareGeek 1 Reply
  • HardwareGeek

    @Gąska said in No external monitor on Ubuntu laptop:

    Embedded.

    Ah, that makes sense.

    @Gąska said in No external monitor on Ubuntu laptop:

    Can you check if booting from Live USB exhibits similar problems?

    Perhaps, but I'd have to find a USB drive that isn't already full-to-overflowing with other stuff, find an Ubuntu image to download, download it, and try booting it. I'm supposed to be using the laptop to do work stuff, not play with the OS. Having an external monitor makes it more convenient to do work stuff, but it's not essential. And I have an external monitor now, even if I can't utilize all the pixels.

    1
  • dcon

    I've had my hdmi monitor die sometimes - but it's only when waking up from sleep. A reboot would typically fix it. Sometimes unplugging/(waitwaitwaitwait)/replugging the cable. But not always.

    2 HardwareGeek 1 Reply
  • dcon

    Oh, and if you have a touch surface on one monitor and not the other? :headdesk: :headdesk::headdesk:

    Here's a script I use:

    #!/bin/sh
# Use xrandr to get display screen name (last arg to xinput)
xinput map-to-output `xinput | grep "USBest Technology SiS HID Touch Controller" | cut -f 2 | cut -d = -f 2` DVI-I-1-1

    The DVI-I-1-1 must be discovered as noted. Also, the name of the touch monitor (from xinput) needs to be pre-determined. Otherwise the touch surface maps to the entire desktop surface.

    1
  • Tsaukpaetra
    Notification Spam Recipient

    IME Linux with multi monitor never really worked properly and everything assumes you have only one screen. Best of luck....

    Maybe some combination of rebooting with the second monitor plugged in or not?

    1
  • HardwareGeek

    @dcon said in No external monitor on Ubuntu laptop:

    A reboot would typically fix it.

    The reboot yesterday (seems to have) caused it. Rebooting again didn't fix it.

    @dcon said in No external monitor on Ubuntu laptop:

    if you have a touch surface

    No touch, on either monitor or laptop screen, so that's not an issue.

    1 C 1 Reply
  • C

    @HardwareGeek Did Ubuntu do any upgrades before the reboot? Maybe it messed up building initramfs or its kernel module cache or something.

    1 HardwareGeek 1 Reply
  • HardwareGeek

    @Captain said in No external monitor on Ubuntu laptop:

    Did Ubuntu do any upgrades before the reboot?

    Not that I noticed, but I really wasn't paying attention to that. I was on the phone with a coworker trying to resolve a VPN problem.

    The internet suggests this (or a similar) problem may be the result of a particular display manager and a change in a default setting that Ubuntu back-ported to 18.04, but that was over 2 years ago. I wouldn't expect an update yesterday to affect that, and it may or may not be specific to Nvidia drivers, which is not relevant to this box.

    1 C 1 Reply
  • C

    @HardwareGeek OK, well, I'd start by looking at dmesg, lspci (for sanity, make sure the PC can see the card's pci interface), and /var/log/boot.log.

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