Hi,
I'm using sys-kernel/gentoo-kernel without any modifications.
kernel 6.12.xx works perfectly fine, but the kernels 6.18.8 and 6.18.12 (usually) freeze when I connect a usb-c hub with connected monitor.
When it freezes, keyboard and mouse stop working, caps-lock starts blinking (?) and the laptop screen freezes as well. The connected monitor does not turn on, and the only thing I can do is force power off by holding the power button.
I am unsure what is causing these freezes, because on occasion it has worked with 6.18 as well... (for 6.18.8 I thought worked if i used the touch-pad before connecting but was not reproducible today so maybe not... 6.18.12 worked once no issues then next reboot it didn't... can't give any more details)
My device is a HP Spectre laptop, using a thunderbolt usb-c to connect to a lenovo thinkpad thunderbolt 3 dock, which in turn is connected to a dell monitor through displayport.
Closest related issue I've found was https://github.com/linux-surface/linux- ... ssues/1980, but the solution is just that a different kernel fixed it...
I'm guessing it's a kernel module that sometimes does not load? But in all honesty I have no idea what's going on.
At the moment I'm just using 6.12, so there's no urgency but if anyone has any ideas I'd appreciate the help.
Cheers!
gentoo-kernel-6.18 freezes when connecting usb-c hub
Message
Welcome to the forums. A blinking caps lock suggests that your kernel panicked, after which point it will be in a tight loop and completely unresponsive. That is consistent with your observation that forced power off is the only thing that works.
You write that 6.18.x is at least intermittently bad. What about 6.19.x? (Note that 6.19.x is currently behind the testing keyword, so Portage will not offer it to a stable-only user. You can override this keyword check to get 6.19.x anyway.)
If you can reproduce this with any regularity, my first attempt would be to switch to a text console, then reproduce it, in the hopes that the kernel panic will produce useful output on the text screen. Since the kernel will be unresponsive after the failure, you will not be able to use the computer to save the text. Take a picture or transcribe the text by hand. (There are other, more exotic, options such as serial console or netconsole. I'm assuming that the laptop won't have serial, and that you don't have a system to act as the other end of the netconsole. Manual capture of the laptop's screen is tedious, but has the fewest prerequisites.) If you want to share the picture, these forums do not allow embedding, so you will need to upload it elsewhere and link to it here. If you choose that route, please check that the picture quality is sufficient that someone else could transcribe it, if needed. Blurry text will not let us see what we need.
You write that 6.18.x is at least intermittently bad. What about 6.19.x? (Note that 6.19.x is currently behind the testing keyword, so Portage will not offer it to a stable-only user. You can override this keyword check to get 6.19.x anyway.)
If you can reproduce this with any regularity, my first attempt would be to switch to a text console, then reproduce it, in the hopes that the kernel panic will produce useful output on the text screen. Since the kernel will be unresponsive after the failure, you will not be able to use the computer to save the text. Take a picture or transcribe the text by hand. (There are other, more exotic, options such as serial console or netconsole. I'm assuming that the laptop won't have serial, and that you don't have a system to act as the other end of the netconsole. Manual capture of the laptop's screen is tedious, but has the fewest prerequisites.) If you want to share the picture, these forums do not allow embedding, so you will need to upload it elsewhere and link to it here. If you choose that route, please check that the picture quality is sufficient that someone else could transcribe it, if needed. Blurry text will not let us see what we need.
Hi, Thank you for the reply 
I tried with kernel 6.19.3 and it encounters the problem less often, but it's still there.
I've made a video of the tty, where I plug in the usb-c hub - then unplug it, then plug it in again (and the second time it crashes). This is with 6.19.3:
https://drive.switch.ch/index.php/s/4RyraOTHBq7FZQs
Usually when it crashes with 6.19.3 the screen goes black. (In general on 6.19.3 the laptop screen goes black for a 2-3 seconds, and then both monitor and laptop screens start working - or caps-lock starts blinking, whereas on 6.18.x the screen does not go black, but freezes instead.).
Here are 2 pictures I took from when 6.18.12 crashed:
https://drive.switch.ch/index.php/s/wI0nlViL3nDsX4m
https://drive.switch.ch/index.php/s/QGPCXMtoAdxlc7u
But from what I can tell, all of the output is from before the kernel panic but I may be wrong.
I tried with kernel 6.19.3 and it encounters the problem less often, but it's still there.
I've made a video of the tty, where I plug in the usb-c hub - then unplug it, then plug it in again (and the second time it crashes). This is with 6.19.3:
https://drive.switch.ch/index.php/s/4RyraOTHBq7FZQs
Usually when it crashes with 6.19.3 the screen goes black. (In general on 6.19.3 the laptop screen goes black for a 2-3 seconds, and then both monitor and laptop screens start working - or caps-lock starts blinking, whereas on 6.18.x the screen does not go black, but freezes instead.).
Here are 2 pictures I took from when 6.18.12 crashed:
https://drive.switch.ch/index.php/s/wI0nlViL3nDsX4m
https://drive.switch.ch/index.php/s/QGPCXMtoAdxlc7u
But from what I can tell, all of the output is from before the kernel panic but I may be wrong.