Public bug reported:
- 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
** Affects: xserver-xorg-video-ati (Ubuntu)
Importance: Undecided
Status: New
** Tags: hdmi radeon
** Attachment added: "Xorg.0.log"
https://bugs.launchpad.net/bugs/1375486/+attachment/4219658/+files/Xorg.0.log
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which is subscribed to xserver-xorg-video-ati in Ubuntu.
https://bugs.launchpad.net/bugs/1375486
Title:
Blank screen when monitor is turned on after boot
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