console displays out of sync after gdm loads

On one of our 2 servers on boot the console screen is normal and legible up until the point gdm loads. That loads fine and the display is OK. However the boot console Alt-F1 and the log console Alt-F10 and all of the other text mode screens are then out of sync and seem to be trying to display in a mode the screen can’t handle.

This server has a graphics card which cannot take the full 1920x1080 the monitor is capable of. That is one of the differences beteen the servers. They share the monitor via a KVM.

So the question is why does the screen resolution/refresh rate for consoles get changed when gdm starts and where do i go to configure this? I have found a lot about the console not being legible on first boot but not about this situation. Changing the properties of the GDM display does not seem to have any effect.

Check YaST → System → Boot Loader and the ‘Kernel Parameters’ tab is anything set in the vga mode and then down the bottom the console resolution?

In the Boot Loader I don’t see a Kernel Parameters tab. I do have a Section Management tab and I have looked at the settings for the default Boot image. That has a vga mode which is set to 0x31a. (That brings back vague memories of DOS settings?)

Won’t this just configure the screen on boot, after grub? I tried setting this to 0x317. After that the screen still goes out of sync after gdm starts but in a different way (worse).

What version of SLES? Are you using the ncurses version of YaST?

If <= 11 SP3 then what graphics card do you have?

/sbin/lspci -nnk|grep -A3 VGA

If it’s not SLE 12, then you can run (switch to runlevel 3 first);

sax2 -r -m 0=<driver from above>

This should sort it all out.

Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.36-38-default
If you find this post helpful and are logged into the web interface,
please show your appreciation and click on the star below… Thanks!


In order:-

radeon driver

…and yep, that sax2 command sorted it!

Thanks very much!