Hugo Vanwoerkom wrote:
Hi,
In upgrading to 2.6.25 I ran into problems, as follows:
1. When I use linux-image-2.6.25-1-686 or 2-686 from binary or from
source I cannot use vga=791 or I get "undefined video mode number: 317".
When I compile from kernel.org's 2.6.25.3 I don't get that problem. I
filed a bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=481063
I ran into the same problem yesterday, installing Lenny on a new build with an integrated Radeon X1200 GPU.
It turns out that the VESA framebuffer driver (vesafb) is not included in the stock kernel's initrd. (You can check the contents of your own initrd with this sort of incantation: 'gunzip -c /boot/initrd.img-<version> | cpio -t | less'.)
You can get VESA FB working again with some commands like the following:
echo vesafb >> /etc/initramfs-tools/modules
update-initramfs
editor /boot/grub/menu.lst
# edit your favorite "kernel" line to include parameters:
# "vga=<mode#> video=vesafb"
Be careful of the mode#! On my main desktop system, with a GeForce 7950GT card, my preferred mode is 1280x1024 -- and the proper mode# is "795" or "0x31B". On my new Radeon X1200 server, the corresponding mode# is "794" or "0x31A". You can find out authoritative mode# values for your hardware by installing "hwinfo" and running
hwinfo --framebuffer
I solved (1) by installing uvesafb in 2.6.25-2-686 detailed here:
http://wiki.debian.org/HowToUseUvesafbWithDebian
I think this is overkill for most folks, but some people have fun playing around with unusual hacks. (I personally use UVESA FB, but only because I want to control the vertical refresh rate on my virtual terminals.)
I think Hugo's instructions have some errors. For example, he instructs folks to install 'klibc', but later compiles the 'v86d' helper utility against "x86emu" instead of 'klibc':
Install v86d
Go to the directory that contains the v86d code and then:
./configure --with-x86emu
make KDIR=<path of the kernel tree that was compiled above>
make install
To build 'v86d' using 'klibc', the configure command should be
./configure --with-klibc
Also, when updating GRUB's 'menu.lst' file,
Add to a kernel command line the following:
video=uvesafb:1024x768-32,mtrr:3,ywrap
I'm not sure that "ywrap" actually does anything on an AMD64 system. I can
report that on my system it gets ignored and "redraw" is used instead of "ywrap".
Having said all that, I remember how much of a hassle it was to learn how to get
UVESA FB running on Debian. For trying to get helpful information out to the world,
Hugo should be thanked!