On Wed, Apr 18, 2012 at 8:39 AM, Takashi Iwai tiwai@suse.de wrote:
Hi,
I noticed that one machine here gives only the blank output with 3.4-rc's. The bisection lead me to affecting commit:
commit e00e8b5e760cbbe9067daeae5454d67c44c8d035 Author: Alex Deucher alexander.deucher@amd.com Date: Fri Mar 16 12:22:09 2012 -0400
drm/radeon/kms: fix analog load detection on DVI-I connectors
Reverting this commit helped, it goes back to normal.
On this system, the VGA monitor is connected to DVI over a VGA-DVI connector (and even VGA-switcher). So, yeah, it's a strange setup. But a regression is a regression.
I don't think it's a regression per se. Prior to that patch, the analog vga was using the wrong load detect function (it's using the one for DP bridge chips) which returned connector_status_unknown if it was called on an invalid connector. The patch just sets the behaviour back to the original behaviour prior to support for DP bridge chips being added (http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=...). The problem is the driver is not able to detect the monitor on the other side of the KVM (a common problem with KVMs). The real problem is that some desktop environments choose to interpret connector_status_unknown as connected. It's not really viable to always return connector_status_unknown as then all ports would be considered connected when in truth they would not be.
Alex
I'm willing to test any patch.
thanks,
Takashi _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel