Latest deployment BREAKS Debian TTY7

[yhilgjff]

I have been using an Asus laptop with Debian bookworm paired with a USB-C DisplayLink KVM for ~1 year now

It has never 100% worked correctly 100% of the time. The external keyboard and mouse attached on the device always worked fine however. The display never did.

Last autumn, after a kernel upgrade I believe, OH THE JOY, the external monitor automagically started working. At that moment I was finally able to take full advantages of all my DisplayLink's features.

This was short lived.

Yesterday I thought I had found the perfect integration(Read: this project) for my setup so I deployed it. What it really did for me was make things worst by killing my TTY7, making it stay black and offering no cursor/content.

# dmesg | grep evdi
[   15.214465] evdi: [I] Initialising logging on level 4
[   15.214466] evdi: [I] Atomic driver: yes
[   15.214502] evdi: [I] Increasing device count to 4
[   15.214571] evdi: [I] (card2) Opened by Task 761 (systemd-modules) of process 761 (systemd-modules)
[   15.214576] evdi evdi.0: [drm] Cannot find any crtc or sizes
[   15.214783] [drm] Initialized evdi 1.14.4 20240410 for evdi.0 on minor 2
[   15.214794] evdi: [I] Evdi platform_device create
[   15.214859] evdi: [I] (card3) Opened by Task 761 (systemd-modules) of process 761 (systemd-modules)
[   15.214863] evdi evdi.1: [drm] Cannot find any crtc or sizes
[   15.215014] [drm] Initialized evdi 1.14.4 20240410 for evdi.1 on minor 3
[   15.215023] evdi: [I] Evdi platform_device create
[   15.215076] evdi: [I] (card4) Opened by Task 761 (systemd-modules) of process 761 (systemd-modules)
[   15.215080] evdi evdi.2: [drm] Cannot find any crtc or sizes
[   15.215280] [drm] Initialized evdi 1.14.4 20240410 for evdi.2 on minor 4
[   15.215289] evdi: [I] Evdi platform_device create
[   15.215348] evdi: [I] (card5) Opened by Task 761 (systemd-modules) of process 761 (systemd-modules)
[   15.215352] evdi evdi.3: [drm] Cannot find any crtc or sizes
[   15.215530] [drm] Initialized evdi 1.14.4 20240410 for evdi.3 on minor 5
[   15.215538] evdi: [I] Evdi platform_device create
[   15.875981] evdi: [I] (card2) Opened by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.875990] evdi: [I] (card2) Closed by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.875996] evdi: [I] (card3) Opened by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.876000] evdi: [I] (card3) Closed by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.876006] evdi: [I] (card4) Opened by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.876010] evdi: [I] (card4) Closed by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.876016] evdi: [I] (card5) Opened by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.876020] evdi: [I] (card5) Closed by Task 1925 (Xorg.wrap) of process 1925 (Xorg.wrap)
[   15.939269] evdi: [I] (card2) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939285] evdi: [I] (card2) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939411] evdi: [I] (card3) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939417] evdi: [I] (card3) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939544] evdi: [I] (card4) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939550] evdi: [I] (card4) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939669] evdi: [I] (card5) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.939675] evdi: [I] (card5) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996312] evdi: [I] (card2) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996325] evdi: [I] (card2) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996346] evdi: [I] (card3) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996352] evdi: [I] (card3) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996364] evdi: [I] (card4) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996370] evdi: [I] (card4) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996396] evdi: [I] (card5) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   15.996401] evdi: [I] (card5) Closed by Task 1925 (Xorg) of process 1925 (Xorg)
[   16.109289] evdi: [I] (card2) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   16.109479] evdi: [I] (card3) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   16.109647] evdi: [I] (card4) Opened by Task 1925 (Xorg) of process 1925 (Xorg)
[   16.109809] evdi: [I] (card5) Opened by Task 1925 (Xorg) of process 1925 (Xorg)

Looking around, it seems that this condition is also known on another DisplayLink project: DisplayLink/evdi#480

[yhilgjff]

Perhaps the real problem here is am getting this error when my system is not connected to the KVM itself, hence effectively rendering my X session unusable.

[yhilgjff]

After reinstalling xorg-server TTY7 is blank while still giving a "Failed to start lightdm.service" error message.

Of course, purging and reinstalling lightdm will not fix it.

I also purged MATE and installed XFCE, same outcome.

[yhilgjff]

I ended up having to reinstall my whole system. Thanks DisplayLink!