KMS, dual monitors, specify resolution/disable monitor (radeon)

Meson · 05-08-2010, 07:09 PM

I have an integrated Radeon HD 4200, and I'm currently using the 2.6.33 kernel. I have dual monitors: VGA-0 and DVI-0.

I want to disable the VGA-0 at boot, and only turn it on manually later with xrandr. I used to have an intel video card and was able to use the kernel command line with video=LVDS-0:d to disable LVDS-0. Is there anything similar for ATI?

jvaldivia · 05-09-2010, 10:46 AM

Did you try to use xrand? I have an nvidia card and I prefer xrand over any GUI application at the end I believe all the GUI uses xrand.

This is the command I use:

xrandr --output VGA-0 --mode 1024x768 --pos 0x0 --output DVI-0 --off --output S-video --off --output LVDS --off

I wrote an small howto here: http://soad1982.blogspot.com/2009/07...esolution.html I hope it helps.

Meson · 05-09-2010, 11:22 AM

I can use xrandr. I want it to be disabled at boot time.

DVI-0 is 1680x1050 - my computer monitor
VGA-0 is 1280x768 - a tv for movies and such

Most of the time I'm only using DVI-0. When they are both plugged in during boot, the resolutions are set correctly on each screen, but because they are showing the same thing, only 1280x768 of my 1680x1050 monitor is being used. I want to use the full 1680x1050 on DVI-0.

Meson · 05-10-2010, 08:17 PM

The kernel (drm) was seeing the monitor as VGA-1. So video=VGA-1:d in the kernel command line works.

Now the problem is that I can't enable it manually with xrandr.

jvaldivia · 05-11-2010, 02:49 PM

Maybe you can use grandr, it's the best GUI I found to configure multiple desktops