[SOLVED] Problem with 1280x1024 framebuffer and grub

d2v · 2007-11-02 10:25:00

I want to use a 1280x1024 framebuffer. So I added 'vga=793' to the grub configuration file as follows

# (0) Arch Linux
title  Arch Linux
root   (hd0,0)
kernel /vmlinuz26 root=/dev/sda2 ro vga=793
initrd /kernel26.img

However, grub gives an error - 'Bad mode number' when I boot with above configuration. The available modes range from 80x25 VGA to 80x60 VGA framebuffer. Grub also gives an option to scan for additional modes, but it can't find any additional mode.

Here is the output of lspci

[devendra@Arkantos ~]$ lspci
00:00.0 Host bridge: nVidia Corporation nForce2 AGP (different version?) (rev a2)
00:00.1 RAM memory: nVidia Corporation nForce2 Memory Controller 1 (rev a2)
00:00.2 RAM memory: nVidia Corporation nForce2 Memory Controller 4 (rev a2)
00:00.3 RAM memory: nVidia Corporation nForce2 Memory Controller 3 (rev a2)
00:00.4 RAM memory: nVidia Corporation nForce2 Memory Controller 2 (rev a2)
00:00.5 RAM memory: nVidia Corporation nForce2 Memory Controller 5 (rev a2)
00:01.0 ISA bridge: nVidia Corporation nForce2 ISA Bridge (rev a4)
00:01.1 SMBus: nVidia Corporation nForce2 SMBus (MCP) (rev a2)
00:02.0 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:02.1 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:02.2 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:06.0 Multimedia audio controller: nVidia Corporation nForce2 AC97 Audio Controler (MCP) (rev a1)
00:08.0 PCI bridge: nVidia Corporation nForce2 External PCI Bridge (rev a3)
00:09.0 IDE interface: nVidia Corporation nForce2 IDE (rev a2)
00:1e.0 PCI bridge: nVidia Corporation nForce2 AGP (rev a2)
01:06.0 Communication controller: Rockwell International HSF 56k Data/Fax/Voice/Spkp (w/Handset) Modem (rev 01)
01:08.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
02:00.0 VGA compatible controller: nVidia Corporation NV18 [GeForce4 MX - nForce GPU] (rev a3)
[devendra@Arkantos ~]$

I have 32 MB shared memory for the onboard video chip. If any more details are required, please let me know. Thanks !

Last edited by d2v (2007-11-02 14:04:35)

[vEX] · 2007-11-02 13:27:58

It's actually 795 and not 793.

Found in my menu.lst:

#  FRAMEBUFFER RESOLUTION SETTINGS
#     +-------------------------------------------------+
#          | 640x480    800x600    1024x768   1280x1024
#      ----+--------------------------------------------
#      256 | 0x301=769  0x303=771  0x305=773   0x307=775
#      32K | 0x310=784  0x313=787  0x316=790   0x319=793
#      64K | 0x311=785  0x314=788  0x317=791   0x31A=794
#      16M | 0x312=786  0x315=789  0x318=792   0x31B=795
#     +-------------------------------------------------+

Last edited by [vEX] (2007-11-02 13:29:08)

d2v · 2007-11-02 13:42:02

Actually I have got something bizarre going on. When I pass vga=793, I get following error-

Undefined video mode number: 319

However, I am able to get the 1280x1024 console with vga=775, vga=794, vga=795. As seen in the table in above post, these numbers correspond to 256, 64k and 16M colours. So the only bad setting is vga=793, i.e. 1280x1024x32K.
Bizarre, isn't it ?
Is anyone else passing vga=793 to their kernel to get 1280x1024x32K framebuffer ? It would be interesting to know how it is working out for them.

Last edited by d2v (2007-11-02 13:44:51)

d2v · 2007-11-02 14:03:43

I think I figured out the issue. I tried the 1024x768x32K (vga=790) framebuffer, and it gives error -

 Undefined video mode number : 316

I think my video card does not support the 32K colour depth. Any other colour depth viz. 256,64K,16M is accepted.
vEX, thanks for the reply.

[vEX] · 2007-11-02 20:15:03

Np, glad it helped and I actually didn't check the other modes to see that 793 is valid. I'm so used to having 795 that I forgot to think about the different number of colors would affect the number, glad you got it working in the end.

Arch Linux

#1 2007-11-02 10:25:00

[SOLVED] Problem with 1280x1024 framebuffer and grub

#2 2007-11-02 13:27:58

Re: [SOLVED] Problem with 1280x1024 framebuffer and grub

#3 2007-11-02 13:42:02

Re: [SOLVED] Problem with 1280x1024 framebuffer and grub

#4 2007-11-02 14:03:43

Re: [SOLVED] Problem with 1280x1024 framebuffer and grub

#5 2007-11-02 20:15:03

Re: [SOLVED] Problem with 1280x1024 framebuffer and grub

Board footer