Video Troubleshooting [Solved]

[nobicycle]

Hi,

Linux video installation is really tiresome.
Consider the old laptop I am installing at the moment with Via graphics.
Toying with the idea of Archbang Linux, I had to add modprobe.blacklist=viafb to the kernel boot parameters to get it started. Once installed, it was too unstable. So ... switch to the best ... Sabayon 10 XFCE amd64.

During installation the graphics display was fine - correct resolution, no issues at all.
On boot up the graphics presented the Sabayon wallpaper, but zoomed in on the "X" of "Sabayon X". No menus, visible. Just a mouse cursor. Apart from cursor movement the system was frozen. Trying to switch to a terminal ALT-CTRL-2 gave a black screen. modprobe.blacklist=viafb did not help.

Rebooting into revovery, X -configure failed with "Number of screens does not match number of detected devices"
startx took several seconds, but eventually two terminal prompts appeared in windows with white background.
xrandr shows an * next to 1920x1200.

Xorg config is here: http://bpaste.net/show/67032/

Any advice would be much appreciated. Does anyone know of a detaled Linux video troubleshooting guide?

Best wishes

[Fitzcarraldo]

Have you tried booting the LiveDVD, pressing F5 when the menu is displayed, and appending xdriver=via to the kernel boot line? If that doesn't work, then xdriver=vesa might work.

[nobicycle]

Thanks Fitzcarraldo.
Those suggestions gave the same result.
By the way the problem is in the Installed environment. The LiveDVD works fine. The installed system boots up apparently normally (as judged by the boot up output) but when the desktop arrives it is heavily "zoomed in", no menus, only a cursor is active. Switching to a terminal to debug the situation is not possible - a frozen black screen results.

I think video troubleshooting is a big problem to potential new Linux users, especially those with laptops. Those users do not seem to face that problem with MAC or Windows - these always seem to boot with some form of working display with a default driver. A comprehenvive step by step video troubleshooting guide is needed for Linux.

[Fitzcarraldo]

It's not that easy, as there are hundreds of different possibilities because there are so many different models of GPU and because each Linux distribution is slightly different. Your step-by-step guide would end up being the size of War and Peace (or a bowl of spaghetti if it were a flow chart). The best thing is an Internet search engine and good Google fu.

What model of VIA GPU is it, and what model of laptop is it? As the LiveDVD works fine, please post the output of the following commands issued as root user in a Terminal window:

Code: Select all

lspci
lsusb
lsmod
cat /boot/grub/grub.cfg
cat /etc/conf.d/modules
cat /etc/modprobe.d/blacklist.conf
cat /etc/X11/xorg.conf
ls /etc/X11/xorg.conf.d/
cat /etc/X11/xorg.conf.d/*
cat /var/log/Xorg.0.log

[nobicycle]

Hi Fitzcarraldo, I solved it by hacking the xorg.conf generated by X -configure, simplifying it to just one screen etc. Maybe the modprobe & xdriver and versafb on the kernel boot line I added made a difference. Not sure yet because I haven't rebooted to test.

I don't mean a guide to all possible configurations. I mean a troubleshooting guide, along the lines of:
1. Display works, but is faulty (my case) => X11 config
2. Display fails completely => driver config => lspci and modprobe to find out hardware and driver loaded + how to change the driver
3.etc


Manual hacking of X11 is not for the average user. Then there's the question of why a livecd would manage a correct config and a permanent install would fail to do so. linuxfoundation.org also put video config as the number one issue by far affecting users. Mac and Windows users appear to have an easier time of it.

[Fitzcarraldo]

It would be helpful if you posted the make and model of your laptop, the lspci output and the xorg.conf that works. That way other users with the same problem in future may find it when they search.

[nobicycle]

Not likely I will see the Notebook for some time. It diid not belong to me. The solution was simply to remove all but on screen from xorg.