radeon 9000 (rv250) dvi 1920x1200 troubles

[Alex Deucher]

On Tue, May 13, 2008 at 8:10 AM, Andre Puschmann
<andre.puschmann at stud.tu-ilmenau.de> wrote:
> Hey folks,
>
>  I am having problems to get my brand new 24" tft to work with its native
>  resolution of 1920x1200px.
>
>  Its a VideoSeven V7 D24W33 and its connected via DVI to a Dell Latitude
>  D600.
>  I am using Ubuntu 7.10 but I also tried 8.04 (live-cd) with the same
>  results.
>  Xrandr detects the monitor and even its resolutions successfully.
>  However, if i try to switch to 1920x1200 the tft stays black.
>
>  I guess there is something going wrong with the video frequencies. But I
>   am not sure what.
>  I also tried a bunch of modelines found with google and also generated
>  with cvt.
>
>  The maximum resolution I get is 1680x1050.
>
>  Any comments are more than welcome.

(II) RADEON(0): Modeline "1920x1200"x60.0  154.00  1920 1968 2000 2080
1200 1203 1209 1235 -hsync +vsync (74.0 kHz)

the problem is you are using xserver 1.3 which had a bug when parsing
sync polarity from edid.  the sync polarities are reversed and many
LCDs don't like that.  try the following modeline:
Modeline "1920x1200R"  154.00  1920 1968 2000 2080  1200 1203 1209
1235 +hsync -vsync

xrandr --newmode "1920x1200R"  154.00  1920 1968 2000 2080  1200 1203
1209 1235 +hsync -vsync
xrandr --addmode DVI-0 "1920x1200R"
xrandr --output DVI-0 --mode "1920x1200R"

Check to see if your distro provides a patch to fix that or upgrade to
a newer xserver.

Alex