https://bugzilla.kernel.org/show_bug.cgi?id=71461
Bug ID: 71461 Summary: monitor doesn't get detected after boot Product: Drivers Version: 2.5 Kernel Version: 3.13.5 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: tom.ty89@gmail.com Regression: No
My card is Radeon HD5850.
The result might varies between different boot. Either the screens would not be detected at all or they seem to be detected with a non-optimal resolution (in console, while gdm shows a broken screen)
If a monitor is connected before boot, others can get detected correctly afterwards.
If only one monitor is connected, turning it off can make the signal lost. Reboot or suspend/resume (after turning it on again) can bring the signal back. (Yet dpms would cause no problem at all)
The only way to reproduce the problem if DVI is involved is to disconnect it physically, otherwise only powering off the monitor is required. My guess is DVI detects display with a different mechanism.