Bug 29941

Summary: radeon/KMS: Screen hotplugging does not work
Product: DRI Reporter: Daniel Klaffenbach <danielklaffenbach>
Component: DRM/RadeonAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: medium    
Version: DRI git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
i915 platform: i915 features:
Description Flags
Xorg log file
dmesg from linux 2.6.36-rc3 with drm.debug none

Description Daniel Klaffenbach 2010-09-01 09:32:08 UTC
I noticed that in recent kernel versions the runtime detection of newly added monitors does not work properly.

When I plug in my TV (DVI2HDMI) after booting I cannot enable it. xrandr correctly shows a new screen and I can even enable the output, but the TV screen stays black. Restarting X does not help.

The driver also seems to recognize the port status after plugging it in (/sys/class/drm/card0-DVI-I-2/status) changes from "disconnected" to "connected".

When I plug the HDMI cable in _before_ booting my computer the TV works just fine.

GFX: Radeon HD 3870
Linux: 2.6-git (issue appeared in 2.6.35) with KMS
Mesa: git
libdrm: git
xf86-video-ati: git
Comment 1 Alex Deucher 2010-09-01 09:36:48 UTC
What was the last kernel version where this worked?  Is the issue still present in 2.6.36rc3?  Can you attach your dmesg output and xorg log?
Comment 2 Daniel Klaffenbach 2010-09-01 10:37:14 UTC
Created attachment 38360 [details]
Xorg log file
Comment 3 Daniel Klaffenbach 2010-09-01 10:37:52 UTC
Created attachment 38361 [details]
dmesg from linux 2.6.36-rc3 with drm.debug
Comment 4 Daniel Klaffenbach 2010-09-01 10:39:48 UTC
(In reply to comment #1)
> What was the last kernel version where this worked?  Is the issue still present
> in 2.6.36rc3?
I remember that this worked just fine in 2.6.34. The problem was introduced in an early RC of 2.6.35 and is still present in 2.6.36-rc3.
Comment 5 Alex Deucher 2010-09-01 11:45:59 UTC
Any chance you could bisect it?
Comment 6 Daniel Klaffenbach 2010-09-02 11:37:25 UTC
(In reply to comment #5)
> Any chance you could bisect it?
I just experiented a bit and it didn't work with neither with This is why I assume that screen hotplugging never worked with KMS on my R600 - I must have confused it with fglrx which I was also using until now.

And I forgot to say something about the logs I did attach yesterday: the logs are from a system which booted without a second screen attached. After the XSession loaded I plugged in the monitor and enabled it with xrandr.
Comment 7 Martin Peres 2019-11-19 08:15:27 UTC
-- GitLab Migration Automatic Message --

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