Dual Output on Mobility Radeon HD 3470

[Richard Palmer]

Dear Alex,

> >
> Does forcing a dpms cycle (xset dpms force off) help? 

No difference.

> Also, you might
> have better luck with xf86-video-ati from git master as 6.12.4 does
> not have full support for displayport.

Right, that has changed things!. I've still only got one monitor working
(the other one compared to the default before), the resolution
is now at 1360x768:

[richardp at salako ~]$ xrandr 
Screen 0: minimum 320 x 200, current 2720 x 768, maximum 2720 x 768
DisplayPort-1 disconnected 1360x768+1360+0 (normal left inverted right x
axis y axis) 0mm x 0mm
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
  1360x768 (0x4d)   84.8MHz
        h: width  1360 start 1432 end 1568 total 1776 skew    0 clock
47.7KHz
        v: height  768 start  771 end  781 total  798           clock
59.8Hz

(I changed the Virtual size in xorg.conf from 3360x1050 to 2720x768 to see
if both monitors worked at that resolution but it's made no difference).

and any xrandr command I run (--auto, --pos, --mode) causes the working
monitor to black out and I have to quit X and get back to the console
to view anything.

regards,

Richard

-- 
Richard Palmer			| Centre for E-Research &
Systems Manager			| Centre for Computing in the Humanities
richard.d.palmer at kcl.ac.uk	| King's College London
Tel: 0207 848 1973