Bug 15155

Summary: [G33]xrandr can not get right mode values
Product: xorg Reporter: Pi, Fengming <fengming.pi>
Component: Driver/intelAssignee: Hong Liu <hong.liu>
Status: VERIFIED NOTABUG QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: git   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
xorg log file none

Description Pi, Fengming 2008-03-20 20:25:07 UTC
Created attachment 15357 [details]
xorg log file

System Environment:
--------------------------
--Platform:G33
--Architecture: 32-bit and 64-bit
--2D driver: git commit:d72e18c10995079121eded758a60ed99b5b8ce1a
--3D driver: Mesa master commit: f7cfc51b057d9d2fa109b32796b992e8f4f3bfcc
--DRM:   git commit:d18c2c684229ec6923e1a578ae837f34e6b97422
--Xserver:  git commit:afd7428690d87097117ab20335658f6d59d60103
--Kernel: 2.6.23

Bug Description:
I connect a 20 inch widescreen to G33 machine. then xrandr -q only get following mode values:
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 2048 x 2048
VGA connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*+
   800x600        60.3
   640x480        59.9
Reproduce steps:
xrandr -q
Comment 1 Michael Fu 2008-03-21 06:42:16 UTC
would you please provide more info according to http://www.intellinuxgraphics.org/how_to_report_bug.html? thanks.
Comment 2 Hong Liu 2008-03-24 18:45:31 UTC
(In reply to comment #1)
> would you please provide more info according to
> http://www.intellinuxgraphics.org/how_to_report_bug.html? thanks.
> 

No need for this bug, the problem is our driver can't get the EDID data with our two G33 machine.

It's still unclear why I2C fails on these two machines.

Thanks,
Hong
Comment 3 Hong Liu 2008-03-26 19:14:14 UTC
I've found the root cause of the problem.

The VGA cable we are using is too long, this causes the bit error on the i2c bus when transferring the EDID data.

Changing to a short VGA cable solves the problem.
Comment 4 Pi, Fengming 2008-03-26 19:29:47 UTC
(In reply to comment #3)
> I've found the root cause of the problem.
> The VGA cable we are using is too long, this causes the bit error on the i2c
> bus when transferring the EDID data.
> Changing to a short VGA cable solves the problem.

So unusual problem,hehe.Good Job!

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.