video problem after upgrade to 20.04
by aal from LinuxQuestions.org on (#56DDH)
Hi All,
This problem should be an easy fix, but I have no idea how to start to research this question.
I had, for some time, been running my dell laptop (Xubuntu 19) with an external lenovo monitor (using mode 1366 x 768) on the HDMI port, and the laptop monitor disabled.
I decided, perhaps foolishly, to accept an upgrade to Ubuntu 20.04, without disconnecting that external monitor or enabling the laptop screen. The whole upgrade went fine, until the time came to restart....
Upon restarting the computer, it comes to the login screen as normal. The display is fine at the login screeen.
However, after putting in my password, when it logs in the screen goes crazy. Everything that should be vertical goes diagonal.
So, I played around a bit and found out that if I unplug the Lenovo and reinsert the cable, the problem is "fixed", both external and laptop monitors do work fine, but only with the Lenovo set to the 1920 x 1080 mode and the laptop on 1366 x 768.
If I try to change those settings, the diagonal chaos ensues. (I think I can turn the laptop screen on and off, but I don't want to test that now, as I may not be able to get back to this post if I do.)
Any ideas?
Thanks in advance,
Andrew.
This problem should be an easy fix, but I have no idea how to start to research this question.
I had, for some time, been running my dell laptop (Xubuntu 19) with an external lenovo monitor (using mode 1366 x 768) on the HDMI port, and the laptop monitor disabled.
I decided, perhaps foolishly, to accept an upgrade to Ubuntu 20.04, without disconnecting that external monitor or enabling the laptop screen. The whole upgrade went fine, until the time came to restart....
Upon restarting the computer, it comes to the login screen as normal. The display is fine at the login screeen.
However, after putting in my password, when it logs in the screen goes crazy. Everything that should be vertical goes diagonal.
So, I played around a bit and found out that if I unplug the Lenovo and reinsert the cable, the problem is "fixed", both external and laptop monitors do work fine, but only with the Lenovo set to the 1920 x 1080 mode and the laptop on 1366 x 768.
If I try to change those settings, the diagonal chaos ensues. (I think I can turn the laptop screen on and off, but I don't want to test that now, as I may not be able to get back to this post if I do.)
Any ideas?
Thanks in advance,
Andrew.