[solved] T420s Problems with acpi after changing fan

[ThinkingPaul]

Hi folks

I have a T420s with Intel GPU running Linux.
As the system was loud and hot I decided to clean the fan and to replace the thermal paste.
After reassembling everything Linux refused to start.
The moment when the graphical login should appear the notebook turns off (better: restarts).
Only when I apply the kernel parameter "acpi=off" I can login into the desktop.

I have no idea what's missing nor which logfiles to check for more information.

Thank you for any suggestion.
Paul

[jaspen-meyer]

Hi, welcome to the thinkpad forum.

Code: Select all

~$ man dmesg
~$ dmesg

That's a baffling sequence. A few ideas I'd try:
- reset bios (remove cmos, power, battery and push power button for 10 seconds. Then login to bios and 'restore to defaults')
- boot from another media (with the idea of [possibly] side-stepping a kernel, or system, misconfiguration)

[axur-delmeria]

jaspen-meyer,

Recent kernels require root privileges for dmesg, so he may need to sudo or or su -c for that.

[ThinkingPaul]

I already did a CMOS reset with no avail.
Also a different system (Debian) did not run.

When I start the system with Kernel parameter "nomodeset" I can login into the graphical desktop, but the screen resolution is only 1024x798.
The output of dmesg can be found here: https://oc.edv-sommer.de/index.php/s/I7o8k8SFUqy1PxC

When I try to switch from the graphical desktop to a text condole (with Ctrl-Alt-F1) a weird things happen. Hard to describe. See the video here: https://oc.edv-sommer.de/index.php/s/oXTVH2YPqm4xMft

Can this be produced by a defective cable? I did not disassemble the display but pulled the two plugs that connects the display to the mainboard.
Setting the external VGA as the primary display doesn't help, either

[jaspen-meyer]

When I start the system with Kernel parameter "nomodeset" I can login into the graphical desktop, but the screen resolution is only 1024x798.

~$ xrandr # can (maybe) change screen resolution. For example:
https://askubuntu.com/questions/377937/ ... resolution

[ThinkingPaul]

Xrander too only offers 1024x786 as max resolution.
It seems to me as if the the graphics card (or screen?) is not recognized correctly, so Linux uses the standard vga driver.

nomodeset isn't a permanent option anyway. It prevents suspend and switching to the text console.

[ThinkingPaul]

Problem solved with a new used mainboard for 50€.