Monitor turns off during boot

Question

I have just done a dist-upgrade to squeeze on my Debian Lenny box and I'm having problems after a reboot.

Boot starts okay and I get the grub screen where I can choose normal or single-user mode. Choosing either of these starts the boot process and it gets as far as asking for the password to decrypt my disk.

After I give the password (correctly) some text scrolls too fast to read and then the monitor goes to standby.

I have tried:

• Single-user mode: does the same thing
• Checking disk encryption password: It is definitely correct as I tried a different value which was not accepted.
• Two different monitors, both with the same result
• Booting from a Kubuntu live disk I have I was able to mount my drive and look in /var/log, but nothing seems to be written there...
• Pinging the box with no success even after leaving it half an hour (incase it was booting but I had a display problem). Can't SSH either.

Any help appreciated!

Answer 1

It sounds like you've got a graphics driver in there that your system reeeeally doesn't like. It could well be some other driver causing a kernel panic, but without more information we don't know.

There are two graphics drivers to worry about: one loaded during boot for the console framebuffer; one loaded a bit later for X. If single-user mode encounters the same problem, X isn't the problem, but the console framebuffer could be (and it doesn't eliminate the potential that another driver is causing the problem.)

You can try disabling the framebuffer at boot time by passing the parameter "nofb" or "vga=normal" to the kernel. If this works, add the parameter to Grub's kernel line (in menu.lst) or experiment to see if another framebuffer driver works better with your system.

Answer 2

maybe debian is using a very high resolution

Answer 3

When the monitor goes to standby, does the PC's power light stay on? Is there hard disk activity? Can you mount the encrypted drive from Kubuntu and read it using the LiveCD? You mention checking /var/log and finding nothing, but it would still be helpful to edit your question and quote the last 20 lines or so of /var/log/syslog. You might also pass the kernel parameter "loglevel=6" which would cause more information to be written to syslog.