black screen when HDMI re-plugged

[Manolo Díaz]

Hi,

Recently, after resume from suspend or just switched off-on the TV, the
screen gets sometimes frozen. I'm still able to switch to a vt. Trying
to reconfigure with "xrandr --output HDMI-0 --auto" shows “Configure
CRTC 0 failed”.

The normal xrandr output on my system is:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
HDMI-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 886mm x 498mm
   1920x1080     60.00*+  50.00    59.94    30.00    24.00    29.97    23.98  
   1920x1080i    60.00    50.00    59.94  
   1600x900      59.98  
   1280x1024     60.02  
   1280x720      60.00    50.00    30.00    59.94    29.97    24.00    23.98  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       60.00    59.94  
DVI-0 disconnected (normal left inverted right x axis y axis)
VGA-0 disconnected (normal left inverted right x axis y axis)

But differs when failed:
--- Success	2015-05-21 11:37:27.818699765 +0200
+++ Failure	2015-05-21 11:38:09.879434401 +0200
@@ -1,6 +1,6 @@
 Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
-HDMI-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 886mm x 498mm
-   1920x1080     60.00*+  50.00    59.94    30.00    24.00    29.97    23.98
+HDMI-0 connected (normal left inverted right x axis y axis)
+   1920x1080     60.00 +  50.00    59.94    30.00    24.00    29.97    23.98
    1920x1080i    60.00    50.00    59.94

Also, looking at "xrandr --verbose" output I can see that the line

	CRTC:       0

disappears.

This bug appeared after upgrading my system (Debian testing, custom
Linux kernel 4.0.4):
xserver-xorg      		7.7
xserver-xorg-video-radeon	7.5.0

Any idea about what's happening?

Best Regards,
-- 
Manolo Díaz