Bug 31972

Summary: 2.6.38.1: radeon hd 6870: kms, hdmi, signal is correct only for 1-2 seconds
Product: Drivers Reporter: Arkadiusz Miskiewicz (arekm)
Component: Video(DRI - non Intel)Assignee: drivers_video-dri
Status: RESOLVED OBSOLETE    
Severity: normal CC: alan, alexdeucher
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: Subsystem:
Regression: No Bisected commit-id:
Attachments: dmesg with messages
dmesg with drm debug=1

Description Arkadiusz Miskiewicz 2011-03-27 17:03:47 UTC 
Created attachment 52182 [details]
dmesg with messages

I'm using 2.6.38.1 with radeon hd 6870 (http://www.gigabyte.com/products/product-page.aspx?pid=3615#ov) connected only to toshiba regza tv with HDMI connector. Nothing else is connected.

After modprobe radeon KMS kicks in, resolution is changed and everything looks fine for 1-2 seconds. Then signal is lost according to tv and there are tons of:
"[drm:atom_dp_get_link_status] *ERROR* displayport link status failed", some kworker eats 90% of cpu and fans go up.

dmesg attached.
Comment 1 Alex Deucher 2011-03-27 20:38:53 UTC 
Is this a regression?  If so what version worked previously?  It looks like one of the hotplug interrupt is firing repeatedly (maybe a loose/bad cable?).  Can you attach the dmesg output with drm debug enabled (load drm.ko with debug=1)?
Comment 2 Arkadiusz Miskiewicz 2011-03-27 21:00:41 UTC 
Created attachment 52212 [details]
dmesg with drm debug=1

Not a regression since 2.6.37 didn't support this card at all. 

Bad cable... I forgot to mention one important thing. Video card is not connected directly to toshiba tv but through pioneer vsx-920-k amplifier. I just did a test and connected directly to tv. The problem is gone.

So pioneer could be suspected for dirty games but there is no problem with windows working in the same setup (I use 1920x1080 in windows; some gpu hungry games like call of duty 4 etc work fine in this setup), so there is a chance for a radeon drm bug.

dmesg with debug attached.
Comment 3 Arkadiusz Miskiewicz 2011-03-27 21:04:12 UTC 
gdm started nicely when connected directly to TV. Then I changed cable to go through pioneer and... gdm still works fine and no bad things in dmesg.

ps. GPU is becoming very hot when "displayport link status failed" happens.
Comment 4 Alan 2012-08-20 15:18:17 UTC 
If this is still seen with modern kernels please reopen/update thanks