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

["Eneko Lacunza" <enlar@enlar.net>]

Tried with a different monitor (at home), with 1280x1024 native
resolution. This got everything ok. xrandr output (more data follows):
Screen 0: minimum 320 x 200, current 2560 x 1024, maximum 2560 x 1600
VGA-0 connected 1280x1024+1280+0 (normal left inverted right x axis y
axis) 338mm x 270mm
  1280x1024      60.0*+   75.0     59.9     60.0*
  1600x1024      60.0
  1400x1050      60.0
  1440x900       60.2
  1280x960       60.0
  1280x800       60.0
  1152x864       75.0     74.8
  1280x768       60.0
  1024x768       75.1     70.1     60.0
  832x624        74.6
  800x600        72.2     75.0     60.3     56.2
  640x480        75.0     72.8     72.8     75.0     66.7     60.0     59.9
  720x400        70.1
None connected (normal left inverted right x axis y axis)
  1280x800       60.0
  1280x768       60.0
  1024x768       60.0
  800x600        60.3
  640x480        59.9
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis)
261mm x 163mm
  1280x800       60.0*+   60.0
  1280x768       60.0
  1024x768       60.0
  800x600        60.3
  640x480        59.9

Then I've tried to switch the external monitor to a higher res:
enlar@elacunza:~$ xrandr --output VGA-0 --mode "1440x900"
xrandr: screen cannot be larger than 2560x1600 (desired size 2720x900)

Although the xrandr output, I couldn't set a higher res. on that
monitor. X server log does not list modes higher than 1280x1024 in DCC
info for the external monitor.

After this, I have tested using my flat TV as external monitor. I got
same A and B, this time their width is 1360-1280 = 80px . Interesting
also that setting external monitor res. to 1360x768 forced LVDS also
to 768 scanlines... xrandr:
Screen 0: minimum 320 x 200, current 2640 x 768, maximum 2560 x 1360
VGA-0 connected 1360x768+1280+0 (normal left inverted right x axis y
axis) 410mm x 256mm
  1360x768       60.0*+
  1280x768       60.0
  1024x768       75.1     70.1     60.0
  832x624        74.6
  800x600        72.2     75.0     60.3
  640x480        75.0     72.8     72.8     75.0     60.0
  720x400        70.1
None connected (normal left inverted right x axis y axis)
  1280x800       60.0
  1280x768       60.0
  1024x768       60.0
  800x600        60.3
  640x480        59.9
LVDS connected 1280x768+0+0 (normal left inverted right x axis y axis)
261mm x 163mm
  1280x800       60.0 +   60.0
  1280x768       60.0*
  1024x768       60.0
  800x600        60.3
  640x480        59.9

And then, trying to fix LVDS native res:
enlar@elacunza:~$ xrandr --output LVDS --mode "1280x800"
xrandr: screen cannot be larger than 2560x1360 (desired size 2640x800)

Quite funny, since we're already with current width at 2640 :)

Now I'll try Xserver 1.5 from experimental, I'll try to send test
results this night, but I can't make any guarantee - otherwise I'll
post them tomorrow morning.

Thanks a lot,
Eneko