Ubuntu 10.04 LTS no video on boot up (KMS issue)

Lee · 30 Nov 2010 at 19:27

Hi, I upgraded to Ubuntu 10.04 LTS from an earlier version a few months back. When the install was complete I rebooted,but I get no video output on reboot. I can tell that the OS has loaded as I get the tune when it boots up.

I did a bit of research at the time, and the following "bug" seems to fit:

"Working around bugs in the new kernel video architecture
Ubuntu 10.04 LTS enables the new kernel-mode-setting (KMS) technology by default on most common video chipsets. While this is a major step forward for the graphics architecture in Ubuntu, in some rare cases KMS will prevent your video output from working correctly, or from working at all. If you need to disable KMS, you can do so by booting with the nomodeset option. You can also save this setting so that it's applied at every boot by adding it to your grub config (for GRUB 2: edit /etc/default/grub and add nomodeset to GRUB_CMDLINE_LINUX, then run sudo update-grub; for GRUB 1: edit /boot/grub/menu.lst and add nomodeset to the line beginning with # kopt=, then run sudo update-grub). (533784, 541501) "

I'm fairly confident that disabling KMS will resolve my issue. my question is, how do I do this. It's easy enough to edit Grub for "nomodeset", however without any video ouput I can't do this...... :confused:

I'm running Grub 2 I think.

I don't use Ubuntu as my main OS, so I just left it. However it's starting to bug me now. I've done some research and everything points to this as the issue, but nothing suggests a practical solution for me.

Anyone got any ideas ?

Lee.

masterluke · 30 Nov 2010 at 19:41

can you change tty? - try doing a ctrl-alt-f1 - do you get a login prompt? if so you can manually login and make the required changes.

if that doesnt work.. can you boot from an ubuntu cd? i think there is an option to boot from the hard disk with amended boot parameters there.

Lee · 30 Nov 2010 at 22:32

Cheers for the ideas masterluke. Will give them a go tomorrow.

JonJ678 · 1 Dec 2010 at 00:50

Assuming the grub menu comes up before ubuntu fails to boot, you should be able to add the appropriate option before booting, then amend grub appropriately after it boots. With grub legacy you hit e, typed away then hit b. I don't know what the command is for grub 2 though, might be the same, might not.

masterluke · 1 Dec 2010 at 11:22

another thought - i think if you hold shift when booting it forces grub2 (which i guess you are on depending upon which version of ubuntu you *orignally* installed) to show its boot menu.

Lee · 1 Dec 2010 at 19:01

Thanks guys.

JonJ678, Ubuntu boots, there is just no video output.

I get the Grub 2 boot menu and have tried to add the "nomodeset" command in teh boot options. I thought I'd done it, but when pressing b to boot, the system restarted and had no effect on the lack of video when Ubuntu boots.

I will try the other suggestions, but I'm in the middle of trying to sort out a different video issue in Windows (crashing when running 3D graphics, not sure if hardware or driver related issue yet).

Happy days.......

masterluke · 1 Dec 2010 at 19:11

The other suggestions are just other ways of adding "nomodeset" to the boot options so wont help if you tried that and it didnt work. Assuming you added the option in the correct place it looks like the KMS issue you found is not your problem.

You dont have a funky monitor hooked up do you? a flatscreen TV or something unusual? What graphics chipset r u on?

Lee · 1 Dec 2010 at 22:56

I'm a bit of a Linux noob, so I'm not convinced I applied the nomodeset option correctly in Grub.

I use a bog standard Viewsonic 19" monitor connected via DVI.

I'm pretty sure I now have a hardware fault with my ATI HD5850, which occured last night (see my post in the Graphics card section), but I'm equally convinced that this has nothing to do with this problem, as I've had this issue with Ubuntu for a few months.

Thanks for your advice. I'll revist this when I get my video card issue sorted.

masterluke · 2 Dec 2010 at 18:34

No worries. Can I suggest that if you are buying new graphics hardware that you move over to nvidia as the linux support is 1000x better.

Lee · 4 Dec 2010 at 18:05

I've recently upgraded from an 8800GTX (which i stupidly sold!!!) to an HD5850. I've bought a cheap HD4350 (didn't want to have to mess around with drivers in Windows)to keep me going whilst I RMA my HD5850.

Never mind, at least I've now proved the HD5850 is faulty, and whilst using the HD4350 I don't get this issue in Ubuntu. I'm going to upgrade to 10.10.