Xrandr not finding modes

Changes · 07-14-2010, 05:17 AM

I'm on Debian Squeeze, my PC has a Radeon HD4770 card. I honestly don't know if it's currently running on OS or proprietary fglrx drivers; I installed fglrx, but the control panel app insists the driver isn't loaded.

I'm following these instructions to try to get my screen running at 1280x960x85. It's currently at 1280x1024x85, but it's an old CRT that, for some reason, works fine at 1280x960 but gets unfocused at 1280x1024.

I'm following the step "adding undetected resolutions", and here's the result:

Code:

fallingwater@longcat:~$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 2048 x 2048
DVI-1 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 406mm x 304mm
   2048x1536      75.0  
   1920x1440      75.0  
   1600x1200      85.0     75.0  
   1280x1024      85.0*    75.0  
   1152x864       75.0  
   1024x768       85.0     75.0  
   800x600        85.1     75.0  
   640x480        85.0     75.0  
   720x400        70.1 
fallingwater@longcat:~$ cvt 1280 960 85
# 1280x960 84.86 Hz (CVT 1.23M3) hsync: 85.79 kHz; pclk: 148.25 MHz
Modeline "1280x960_85.00"  148.25  1280 1368 1504 1728  960 963 967 1011 -hsync +vsync
fallingwater@longcat:~$ xrandr --newmode "1280x960"  148.25  1280 1368 1504 1728  960 963 967 1011 -hsync +vsync
fallingwater@longcat:~$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 2048 x 2048
DVI-1 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 406mm x 304mm
   2048x1536      75.0  
   1920x1440      75.0  
   1600x1200      85.0     75.0  
   1280x1024      85.0*    75.0  
   1152x864       75.0  
   1024x768       85.0     75.0  
   800x600        85.1     75.0  
   640x480        85.0     75.0  
   720x400        70.1  
  1280x960 (0x70)  148.0MHz
        h: width  1280 start 1368 end 1504 total 1728 skew    0 clock   85.6KHz
        v: height  960 start  963 end  967 total 1011           clock   84.7Hz
fallingwater@longcat:~$ xrandr --output DVI-0 --mode 1280x960
xrandr: cannot find mode 1280x960

It lists the mode I just added, but says it can't find it. How do I get it to work?
Thanks.

adamk75 · 07-14-2010, 05:52 AM

You're definitely using the open source driver. The output names for fglrx are different (DFP1, CRT1, etc.). Having fglrx at least partially installed, though, may break your 2D and 3D acceleration with the open source drivers (assuming Squeeze is new enough to support 3D acceleration via the open source drivers).

Anyway... After using --newmode to create a new mode, you need to use --addmode to add that mode to a specific port. Try:

Code:

xrandr --newmode "1280x960"  148.25  1280 1368 1504 1728  960 963 967 1011 -hsync +vsync
xrandr --addmode DVI-0 1280x960
xrandr --output DVI-0 --mode 1280x960

Changes · 07-14-2010, 06:54 AM

Quote:

Originally Posted by adamk75

You're definitely using the open source driver. The output names for fglrx are different (DFP1, CRT1, etc.). Having fglrx at least partially installed, though, may break your 2D and 3D acceleration with the open source drivers (assuming Squeeze is new enough to support 3D acceleration via the open source drivers).

I don't care about 3D acceleration. Regardless, I just aptitude-purged everything fglrx from my system, to be on the safe side.

Quote:

Anyway... After using --newmode to create a new mode, you need to use --addmode to add that mode to a specific port. Try:

Code:

xrandr --newmode "1280x960"  148.25  1280 1368 1504 1728  960 963 967 1011 -hsync +vsync
xrandr --addmode DVI-0 1280x960
xrandr --output DVI-0 --mode 1280x960

I love you

thanks!