Blank screen when monitor is turned on after boot

[Julien Villemure]

- System:

Ubuntu 14.04.1 amd64 (freshly installed from scratch)
Kernel 3.13.0-24-generic #47-Ubuntu SMP
Radeon HD 5450 sending video and audio via HDMI to an A/V receiver, which itself is connected via HDMI to a TV.

- Steps to reproduce:

1) With the computer off, turn on the receiver and the TV
2) Boot computer
3) The login screen appears correctly, everything's fine.
4) Turn off receiver
5) Turn on receiver
6) Blank screen and no sound.
7) I am able to switch to the TTYs by pressing e.g. Ctrl-Alt-F1, but if I try to go back to my X session by pressing Ctrl-Alt-F7, it's still on the blank screen.

My setup is functional with other devices (PS3, Windows) and worked fine with Ubuntu 13.10. This is a new problem in Ubuntu 14.04.1.

- Workaround:
restart lightdm

- Logs:
Xorg.0.log
dmesg.txt

Near the bottom of dmesg.txt there are errors regarding EDID:

[ 43.320174] radeon 0000:01:00.0: HDMI-A-1: EDID block 0 invalid.
[ 43.320179] [drm:radeon_dvi_detect] *ERROR* HDMI-A-1: probed a monitor but no|invalid EDID
[ 48.554222] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 226
[ 49.962580] [drm:radeon_dvi_detect] *ERROR* HDMI-A-1: probed a monitor but no|invalid EDID

[Julien Villemure (phunkatic)]

So.... 3 months later..... anyone??

[Julien Villemure (phunkatic)]

The problem appears to be due to xfsettingsd (part of Xfce4)

https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-331/+bug/1308105