I'm trying to set the screen resolution in /etc/grub.conf
using vga=
on the kernel line:
vga=788
I'm using CentOS 6.4.
That command should set the screen resolution to 16bit 800×600 according to antlinux's wiki.
I removed rhgb
from the grub.conf
file so I can see the details of the boot instead of the progress bar. The problem is that the details on the screen are very small, using and old monitor like most of our customers and changing the VGA setting in grub.conf
doesn't seem to change anything for these details being displayed on the screen or the login prompt at the console.
Any ideas on what to change to modify the screen resolution for the details show on the console during boot and login prompt? Setting VGA in grub.conf
just doesn't seem to do anything.
/etc/grub.conf:
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.32-358.el6.i686)
root (hd0,0)
kernel /vmlinuz-2.6.32-358.el6.i686 ro root=UUID=8676c199-8498-4de4-8465-c87c2138560f
rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD
SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us
rd_NO_DM vga=788 quiet
initrd /initramfs-2.6.32-358.el6.i686.img
UPDATE:
I'm seeing this in /var/log/messages
:
Nov 18 16:01:34 localhost kernel: [drm] nouveau 0000:01:00.0: allocated 1024x768 fb: 0x48000, bo df82e400
I think this has something to do with my problem with the resolution changing on me..Still looking into it. Fixed it!! See fix it post below.
Best Answer
Finally figured it out..This is what worked for CentOS 6.4...Results might vary depending on what version you're using...
UPDATE: I decided not to modify the original post but wanted to make sure that
nouveau.modeset=0
should be replaced withnomodeset
. At least in my case this was a better solution than usingnouveau.modeset=0
which only worked on certain hardware.From looking at
/var/log/messages
, I noticed thatnouveau
, which is needed by plymouth was setting the resolution to 1024x768. This caused the resolution to change even though it had been set to something lower usingvga=ask
in grub.conf. So, the behavior symptoms look like this:vga=
parm.nouveau
kicks in and changes it to the thedefault (1024x768)
ornouveau.modeset=3
. You can see this in/var/log/messages
.Fix it by adding this to the kernel line in
/etc/grub.conf
:It was by default setting it to
nouveau.modeset=3
causing1024x768
even though something else was set using using thevga=
setting... The left hand doesn't know what the right hand is doing in this case. What a pain fixing this was...Argggg!!!! I'm sure there is a reason for doing it this way but it seems likenouveau
should look at thevga=
before defaulting to anything..../etc/grub.conf
:If you are suffering from something similar, check
/var/log/messages
and see whatnouveau
is setting formodeset
and adjust accordingly in/etc/grub.conf
.If you have a custom installation with a kickstart file, you can add this parm on the bootloader line of ks.cfg:
bootloader --location=mbr --driveorder=sda --append="crashkernel=auto nouveau.modeset=0"
Otherwise, I would change it in
/boot/grub/grub.conf
and/etc/grub.conf
If you have a custom install of CentOS and you want to control the resolution from the start of the install, try modifying your isolinux.cfg file: