Bug#531868: xserver-xorg-video-radeon: Secondary display not recognized as connected with All in Wonder 9600

[Alex Deucher]

On Thu, Jun 4, 2009 at 12:00 PM, Brice Goglin <Brice.Goglin at ens-lyon.org> wrote:
> Ian Lewis wrote:
>> Package: xserver-xorg-video-radeon
>> Version: 1:6.12.2-2
>> Severity: normal
>>
>> I have two monitors connected to my All in Wonder Radeon 9600 but only
>> one is recognized as being connected. One monitor displays properly but
>> the other has just a blank screen. Switching to console works as
>> expected (CTRL+ALT+F1) and the output is mirrored on both monitors but
>> switching back to X11 (CTRL+ALT+F7) restores the previous state and the
>> one monitor goes blank again.
>>
>> VGA-0 disconnected (normal left inverted right x axis y axis)
>>       Identifier: 0x4d
>>       Timestamp:  24326
>>       Subpixel:   no subpixels
>>       Clones:     VGA-1
>>       CRTCs:      0 1
>>       Transform:  1.000000 0.000000 0.000000
>>                   0.000000 1.000000 0.000000
>>                   0.000000 0.000000 1.000000
>>                  filter:
>>       load_detection: 0 (0x00000000)  range:  (0,1)
>>
>
> I wonder if load_detection is supposed to be 0 here. Does it help if you do:
>  xrandr --output VGA-0 --set load_detection 1
> and then run xrandr again ?

Load detection is off by default on the tv-dac as you end up with
false positives with tv-out since they share the same dac.  Enabling
load detection may mis-detect the tv as being connected as well.
You'll can also force it on manually using xrandr.  If the monitor in
question does not support ddc, you can also swap the connectors, as
load detection works well on the primary dac and the secondary dac can
use ddc since that monitor supports it.

Alex