Radeon Driver Default Display Resolution

[Alex Deucher]

On Sun, Mar 23, 2008 at 7:55 AM, Greg Treantos <gtreanto at gmail.com> wrote:
> I am running a Gentoo system and after upgrading to x11 7.3 now when I issue
> startx, xwindows starts with a screen resolution of 1152x768 54.8hz. Before
> I upgraded the system would start with whatever I had in the display section
> of xorg.conf. Once the system is up I can use xrandr to switch to my
> preferred 1400x1050 @ 74.8hz.  In xorg.conf I don't have 1152x768 set and I
> have tried commenting out HorizSync, VertRefresh, adding  Option "NoDDC"
> "True", Option "UseEDID" "False",  and HorizSync and source: edid (x would
> not start with option) without success. My question is how does xwindows
> pick this resolution, how can I force x to use the resolutions in the
> Display Subsection or startx with 1400x1050.. Thanks
>

(II) RADEON(0): Found color CRT connected to primary DAC

The driver is not able to get an edid from the monitor so it doesn't
know what modes the monitor supports.  At this point the server
attempts to (rather poorly) pick a mode within the sync ranges of your
monitor as specified in your monitor section.  Ajax has attempted to
fix up the mode selection logic in these cases in newer X servers.
For now you have to specify a preferred mode and possibly some
modelines, depending on the referesh rate you want.  See below.

Alex

> xorg.conf
>
> Section "InputDevice"
>
>      Identifier   "Mouse1"
>      Driver   "mouse"
>      Option "Protocol"    "Auto"   # Auto detect
>      Option "Device"      "/dev/input/mice"
>      Option "ZAxisMapping"   "4 5 6 7"
>
>  EndSection
>
>  Section "Monitor"
>
>      Identifier  "IBM P70"
>      HorizSync   29-82
>      VertRefresh 50-120

Modeline "1400x1050_75.00"  156.00  1400 1504 1648 1896  1050 1053
1057 1099 -hsync +vsync
Modeline "1400x1050_74.80"  155.50  1400 1504 1648 1896  1050 1053
1057 1099 -hsync +vsync
Option "PreferredMode" "1400x1050_74.80"

>
>  EndSection
>
>  Section "Device"
>      Identifier  "** ATI Radeon (generic)               [radeon]"
>      Driver      "radeon"
>  EndSection
>
>  Section "Screen"
>      Identifier  "Screen 1"
>      Device      "** ATI Radeon (generic)               [radeon]"
>      Monitor     "IBM P70"
>      DefaultDepth 16
>
>      Subsection "Display"
>          Depth       8
>          Modes       "1400x1050" "1280x1024" "1024x768"
>          ViewPort    0 0
>          Virtual     1600 1280
>      EndSubsection
>      Subsection "Display"
>          Depth       16
>          Modes       "1400x1050" "1280x1024" "1024x768"
>          ViewPort    0 0
>          Virtual     1600 1280
>      EndSubsection
>      Subsection "Display"
>          Depth       24
>          Modes       "1400x1050" "1280x1024" "1024x768"
>          ViewPort    0 0
>          Virtual     1600 1280
>      EndSubsection
>  EndSection
>
>  Section "ServerLayout"
>      Identifier  "Simple Layout"
>      Screen "Screen 1"
>      InputDevice "Mouse1" "CorePointer"
>      InputDevice "Keyboard1" "CoreKeyboard"
>
>  EndSection
>
>  Section "DRI"
>      Mode 0666
>  EndSection
>