Bug 93753

Summary: Sometimes wrong clk frequency of Display after dpms mode changes.
Product: DRI Reporter: t.graziadei
Component: DRM/RadeonAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: critical    
Priority: high    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Screenshot of failure
none
original test image
none
dmesg output of startup in case of failure
none
Screenshot of failure
none
original test image none

Description t.graziadei 2016-01-18 10:29:56 UTC
Created attachment 121103 [details]
Screenshot of failure

Sometimes after the deactivation of the screensaver or also on bootup the screen shows flickering noise and a duplicated screen image. (Attached there is the used test image and a screenshot of the failure image). 

We tested on various kernel versions, latest kernel tested was 4.4.0. We run a customized debian image. 

Further investigations showed, that in the failure scenario the measured clk frequency was only 25MHz but it should be 35MHz. 

We also tried to deactivate dpms completly (radeon.dpm=0 in kernel parameters) and also turned the dpms off in the screensaver, but we still sometimes encounter the problem after a reboot. 

Attached you will find a dmesg output with drm.debug=0xf activated. 

We use a Radeon PALM on a AMD G-T40E 2x1GHz
Comment 1 t.graziadei 2016-01-18 10:30:56 UTC
Created attachment 121104 [details]
original test image
Comment 2 t.graziadei 2016-01-18 10:31:18 UTC
Created attachment 121105 [details]
dmesg output of startup in case of failure
Comment 3 t.graziadei 2016-01-18 10:32:28 UTC
Created attachment 121106 [details]
Screenshot of failure
Comment 4 t.graziadei 2016-01-18 10:32:58 UTC
Created attachment 121107 [details]
original test image
Comment 5 Alex Deucher 2016-02-05 17:19:59 UTC
What mode are you trying to set?  Please attach your xorg log and and config (if you have one) and the xrandr --verbose output.
Comment 6 Alex Deucher 2016-02-05 17:28:48 UTC
DPM has nothing to do with the display clocks or dpms.  It's engine clock management.  Also which display are you having problems with, VGA or LVDS?
Comment 7 Martin Peres 2019-11-19 09:11:20 UTC
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