DPI changes on radeon dual screen with MetaModes

[Alex Deucher]

On 6/1/06, Richard Stellingwerff <remenic at gmail.com> wrote:
> Hi,
>
> I have a dualscreen setup and I'm using MergedFB to span my desktop
> across the two screens. My MetaModes looks like this:
>
> Option      "MetaModes" "1400x1050-1024x768 1400x1050+1024x768
> 1024x768 800x600 640x480"
>
> This works pretty well, except for a little issue with the DPI
> settings. The DPI keeps changing when I switch resolution, causing
> some applications to behave very oddly with the fonts.
>
> Is there a way to set the DPI to a fixed value? I already tried
> "startx -- -dpi <value>" but this doesn't seem to help.
>
> Here's what happens when I switch between modes:
>
> $ xrandr
>  SZ:    Pixels          Physical       Refresh
> *0   2424 x 1050   ( 641mm x 278mm )  *25179
>  1   1400 x 1050   ( 641mm x 278mm )   -8331
>  2   1024 x 768    ( 641mm x 278mm )   -8331
>  3    800 x 600    ( 641mm x 278mm )   -8337
>  4    640 x 480    ( 641mm x 278mm )   -8343
>
>
> $ xrandr -s 0
> $ xdpyinfo | grep resolution
>  resolution:    96x96 dots per inch
>
> $ xrandr -s 1
> $ xdpyinfo | grep resolution
>  resolution:    55x96 dots per inch
>
> My hardware is:
> ATI Technologies Inc M9+ 5C61 [Radeon Mobility 9200 (AGP)] (rev 01)
> using the radeon driver.
>
> It appears that the "physical size" always counts both screens, even
> in MetaModes where I specify one screen only. If I could just tell the
> driver not to calculate the DPI but use a predefined value, the
> problem would be "solved" for as far as I'm concerned. Can this be
> done?


This is fixed in the radeon driver in cvs and possibly 7.1.

Alex

>
> Kind regards,
> Richard Stellingwerff.