(?) Troubleshooting boot-time video mode problems

From Scott Rafferty

Answered By Joshua Jeffrey Wingstrom, Karl-Heinz Herrman, Matthias Posseldt

In reply to TAG #2, Issue 77


Sorry for the intrusion. Came across your name in a linux archive. Your brother had a similar problem to the one I'm having right now and I was wondering if he managed to resolve the issue. The problem is the blank screen on bootup (no boot messages, no logon prompt etc)...I kinda agree with your hardware/card theory as I too am using a GEFORCE 2 card.

I can get the console text/logon prompt to appear by logging in (although I can't see what I'm typing) and starting X and then quitting X. This seems to "restore the correct mode" and the text logon prompt appears fine.

Booting up rescue mode or doing a text install from the CD seems to show the console text no problem though so why would my newly installed kernel just blank the screen.

(!) [K.-H.] just an idea:
but: At least SuSE's regular boot process shows a penguin or something and therefore must have switched to some non-text console (VGA mode). Maybe your card doesn't like that?
boot messages are of course always readable later on via dmesg, but I agree that if something goes wrong and boot hangs it would be nice to see the messages....

(?) Very little information on this problem in general. It's extremely frustrating. I'd like to see my boot messages. Interestingly enough I've encountered the same problem with Mandrake and Redhat on the same system. I could buy a new card of course but I'm determined to get to the bottom of this.

If I've intruded, please accept my apologies in advance.

Scott Rafferty

(!) [Joshua]
Scott, Thanks for contacting me. I would like to resolve this too.
I have since switched to Gentoo and the problem does not occur there.
I think that the problem is related to the bootsplash screens that Mandrake and Redhat use. The GEFORCE 2 does not seem to want to be switch into... I'm guessing VESA mode?... in the manner in which these applications are switching it. I think that this can be fixed by using the bootsplash utility from Mandrake. The CVS code for this is available at:
I would look at the documenatation and try to turn off the bootscreen. If this fixes the problem, try changing boot screen resolutions. Otherwise, I'm guessing we'll have to start looking at kernel configurations.
Happy hunting, Josh

(?) After scouring google yesterday for an answer to my NO BOOT MESSAGES problem there was one interesting comment I came across about settings in the BIOS. So late last night I made 2 changes to my BIOS settings. Now I can see all my boot messages. A simple but no less important solution to a frustrating problem.

The changes I made to the BIOS were these (screenshot links included) --

Enabled the memory hole from 15-16 M

Changed Primary VGA BIOS to [AGP VGA Card] - Was set to [PCI VGA Card].

(!) [Matthias] I'm pretty sure it is only the second BIOS setting which has to do with the VGA problem. You better disable the first option again, because it's more trouble than it's worth. And it is a "legacy" option, for systems which use VGA cards older then 1994 or so. Almost any system is newer to when this setting was important. In your PC timeline, order it in before "MS Windows 3.0 finally arrived. Bad OS/2 clone, btw." ;-)

(?) Different BIOS's will have different settings of course but I think these two are pretty standard across the board.

One thing to note - I had to actually switch the power off after making the changes (rather than just rebooting) for the changes to take complete effect. I also could have narrowed it down a little further to just the one BIOS change but it was late and I was so elated that I just forgot. If anyone wants me to delve further then just ask.

I really hope this helps other people with the same problem. I'm sure anyone in the know will understand exactly why these 2 settings would effect the linux bootup in such a way with some of the NVIDIA cards. I don't though. :)

Cheers, Scott

(!) [Matthias] It has to do with the AGP way of life ;-). AGP cards have two modes. The "PCI equivalent" simple mode where they can display character mode terminals etc, and the "AGP full featured mode" where they run full power. The second mode has to be supported by the Operating System with some driver and AGP layer.
And it seems that -- while the BIOS can display characters -- Linux cannot display them for some reason. Maybe because it sends PCI only commands or tries to detect the VGA card on the PCI bus and fails correctly handling

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