Comment 17 for bug 410401

Revision history for this message
In , aschuring (aelschuring) wrote :

Firstly: this is getting way off from the original problem. Should I change the summary to reflect this?

(In reply to comment #10)
> xrandr's --current option makes use of this call, which is available
> since xrandr 1.3 and xserver 1.6.
Indeed, I can confirm that $ xrandr --current does not make the screen flicker.

(In reply to comment #11)
> If all of your connectors have a monitor connected, the driver shouldn't even
> be using load detection since it's able to get an edid from the monitor.
I think I understand what's going on now. The flickering is caused by load detection on the S-video port (the only one without a monitor). The non-kms configuration defaults to load_detection=0 on that port, but the flicker appears as soon as I set it to 1:

aschuring@neminis:~$ xrandr --verbose | egrep ^[A-Z]\|load\|CRT
VGA-0 connected [..]
 CRTC: 0
 CRTCs: 0 1
 load_detection: 0 (0x00000000) range: (0,1)
DVI-0 connected [..]
 CRTC: 1
 CRTCs: 0 1
 load_detection: 0 (0x00000000) range: (0,1)
S-video disconnected [..]
 CRTCs: 0 1
 load_detection: 1 (0x00000001) range: (0,1)

In KMS mode however, I can't disable the load detection (or at least it has no effect):

aschuring@neminis:~$ xrandr --verbose | egrep ^[A-Z]\|load
VGA-0 connected [..]
 load detection: 0 (0x00000000) range: (1,0)
DVI-0 connected [..]
 load detection: 0 (0x00000000) range: (1,0)
S-video disconnected [..]
 load detection: 0 (0x00000000) range: (1,0)

With all load detection set to 0, the screen still flickers.