Bug#503664: xserver-xorg-core: Dual head with Radeon HD3200 - heads partly overlay each other

[Brice Goglin <Brice.Goglin@ens-lyon.org>]

Eneko Lacunza wrote:
> And a snippet from Xorg.0.log:
> (EE) RADEON(0): Mode 1360x768+1280+0 does not fit virtual size
> 2560x1360 - offset updated to +1200+0
>   

Ok, so now, the server/driver sees a virtual size problem (that probably
explains your rendering problems with testing/unstable) and it fixes it
by offseting the right monitor monitor.

> Maybe there's some kind of limit in 2560px width in the hw or driver?
>   

Maybe, see below.

> Anyway this version only has produced a black external monitor :)
>   

If you know for sure which resolution+refresh-rate should be used, you
can use ModeLine+PreferredMode in the corresponding screen section. See
section III.5 of http://wiki.debian.org/XStrikeForce/HowToRandR12

> So definitely not a hw limit. Seems a radeon driver issue?
>   

Or maybe a Virtual size config limit? Can you try adding
    Virtual 3000 1600
in the Device section to force the maximal size to be larger?

Then try again with your 1440+1280 setup (with ModeLine+PreferredMode if
needed) with Xserver 1.5 from experimental.

thanks,
Brice