How to adjust screen resolution?

I've installed Debian testing from netist image in a AMD Radeon system. I am using Xorg and awesome wm. The default screen resolution is 1024x768 while my screen supports 1366 x 768.

I've tried xrandr and fglrx but they failed.

A proprietary ATI drivers however solved this problem, but gives a slow scroll effect.

I've also used crunchbang Linux and it displays the corect resolution without a xorg.conf or ATI drivers.

Solution 1:

I have never seen xrandr failing at setting up even the most exotic monitor resolutions, but I have seen it misused very often. I'll post the exact sequence of commands for xrandr. If you have followed the same steps please ignore my answer.

1. Use cvt to calculate the parameters needed by xrandr:

   cvt 1366 768
   

   example output:

   # 1368x768 59.88 Hz (CVT) hsync: 47.79 kHz; pclk: 85.25 MHz
   Modeline "1368x768_60.00"   85.25  1368 1440 1576 1784  768 771 781 798 -hsync +vsync
   

2. build the xrandr command with the output of cvt:

   xrandr --newmode "1366x768" 85.25  1368 1440 1576 1784  768 771 781 798 -Hsync +Vsync
   

   please note Hsync and Vsync capitalized. I needed to do that to get things working on some systems

3. Add a newmode in xrandr:

   xrandr --addmode VGA1 "1366x768"
   

   Replace VGA1 as needed

4. Enable the new resolution:

   xrandr --output VGA1 --mode "1366x768"