Created attachment 105377 [details]
dmesg output with drm debug information

Encountered a strange problem with Radeon HD 6250 (or HD 6310) on a Fujitsu
D3003-S1x mainboard. Occurs with every tested linux distribution and older and
newer kernels. 

Problem occurs only when a monitor is attached via VGA to the DVI port. If the
monitor is attached via DVI then the problem does not occur.

Problem is that
- Monitor is flickering sporadically 
- Monitor resolution is fixed to 1024x768 instead of higher resolutions that
are possible
- xrandr shows 2 monitors while just one monitor is attached

Tried to debug this with kernel parameter drm.debug=14 (dmesg log is attached)
and found the following messages that would explain the flickering screen.

[    4.098364] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[    4.098369] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[    4.219817] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[    4.219830] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[    4.231344] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[    4.231350] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[   13.949336] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[   13.949350] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[   13.967886] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[   13.967891] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[   14.023332] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[   14.023345] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[   14.056688] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[   14.056694] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1

The problem is still to find the root cause that leads to the issue of having
"conflicting encoders". Any idea what could cause this behaviour?

Regards
Rainer