Bug 25218 - radeonhd unreliably reads EDID of a TV connected to VGA_1
Summary: radeonhd unreliably reads EDID of a TV connected to VGA_1
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/radeonhd (show other bugs)
Version: 7.4 (2008.09)
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: Egbert Eich
QA Contact: Xorg Project Team
Depends on:
Reported: 2009-11-21 17:28 UTC by Josip Rodin
Modified: 2011-11-07 15:40 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Description Josip Rodin 2009-11-21 17:28:15 UTC

I've got a Thinkpad T400 (the same one described previously in bug 22279 :) with a Mobility Radeon HD 3400.

When I run Windows (Vista) and plug in my Sony TV into the VGA port on the laptop, that driver notices that something's been plugged in and responds by sending over a normal picture to it, max resolution 1360x768.

However, the Linux driver doesn't seem to get it. xrandr consistently shows that VGA_1 is "disconnected". I can force it, with a script like this: 

xrandr --output VGA_1 --off
xrandr --prop
xrandr --output VGA_1 --auto
xrandr --newmode 1360x768_60.00 84.75  1360 1432 1568 1776  768 771 781 798 -hsync +vsync
xrandr --addmode VGA_1 1360x768_60.00
xrandr --output VGA_1 --mode 1360x768_60.00
xrandr --output VGA_1 --left-of PANEL
xrandr --prop

I often have to run this script several times before it catches on. Eventually however it works, and then the card starts sending output via VGA out.
If I run xrandr --prop, it *occasionally* reports:

VGA_1 connected 1360x768+0+0 (normal left inverted right x axis y axis) 1600mm x 900mm
        _OutputNumber: 3 (0x00000003)
        ConnectorNumber: 3 (0x00000003)
        ConnectorType:  VGA
        SignalFormat:   VGA
                supported: VGA         
   1360x768       60.0 +   60.0  
   1280x768       59.9  
   1024x768       60.0  
   800x600        60.3  
   640x480        60.0  
   1360x768_60.00   59.8* 

Other times, it's just:

VGA_1 disconnected (normal left inverted right x axis y axis)
        _OutputNumber: 3 (0x00000003)
        ConnectorNumber: 3 (0x00000003)
        ConnectorType:  VGA
        SignalFormat:   VGA
                supported: VGA         
   1360x768_60.00   59.8  

In any case, once the picture is turned on, it looks like the driver continues to have some kind of a problem - the picture flickers and keeps getting readjusted, and the Xorg and xfdesktop processes start eating a lot of CPU.

I then proceed to run:
xrandr --output VGA_1 --preferred
xrandr --prop
a few more times, and eventually everything settles down, and I get 1360x768 on the other screen.

Please help :)
Comment 1 Jeremy Huddleston Sequoia 2011-10-16 15:58:48 UTC
Does this issue occur with the preferred ati driver (xf86-vide-ati)?  If so, please move this to the Driver/Radeon component.  

Development of radeonhd has pretty much halted and development focus is on the ati driver.  Please see http://www.x.org/wiki/radeonhd

If the issue does not exist in the ati driver (or if there is no response to this message), this bug will be closed as WONTFIX unless someone contributes a patch.
Comment 2 Jeremy Huddleston Sequoia 2011-11-07 15:40:35 UTC
Closing due to lack of response.  Please reopen and move to the Driver/Radeon 
component if this issue persists with xf86-video-ati

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