Bug 48357

Summary: Display resolutions not detected correctly after startup with VGA over DisplayPort
Product: DRI Reporter: Steffen <heroeschman>
Component: DRM/RadeonAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg none

Description Steffen 2012-04-05 14:12:50 UTC 
Created attachment 59545 [details] [review]
dmesg

Hi.
One of my monitors is a VGA LCD connected over DisplayPort. After startup not all resolutions are detected but only resolutions up to 1024x768. However if i disconnect the monitor and reconnect it again (at 287.472381 in the log file) all screen resolutions are detected correctly.

The initial detection does not work and dmesg shows
"[drm:radeon_dp_i2c_aux_ch], aux i2c too many retries, giving up"
error messages. drm_helper_probe_single_connector_modes() then falls back and probes some modes up to 1024x768 that is why higher resolutions are missing. No idea why it works after reconnecting the monitor.

dmesg log is "dmesg | grep drm" with drm.debug=0x0e from a 3.4-rc1 kernel but the problem already happend in earlier versions. The problem also happens if only the VGA monitor is connected.
Comment 1 Steffen 2014-06-28 14:12:41 UTC 
This bug is finally fixed for me with kernel 3.15.

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