Bug 22466 - [945GM] EDID information of monitor on VGA not detected
Summary: [945GM] EDID information of monitor on VGA not detected
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: git
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: MaLing
QA Contact: Xorg Project Team
URL: https://bugs.launchpad.net/ubuntu/+so...
Keywords: regression
Depends on:
Reported: 2009-06-25 02:20 UTC by Geir Ove Myhr
Modified: 2009-06-30 02:14 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Description Geir Ove Myhr 2009-06-25 02:20:29 UTC
Forwarding a bug from a ubuntu user:

Bug description:
With a LCD LG TV 19LS4D connected to the VGA port on a Sony VAIO vgn-sz1m, the EDID information is not detected. The EDID information is detected with the 2.4 version of the driver, but not with 2.6.3 and above (also tested with 2.7.99). This results in the native resolution of the external monitor (1440x900) not being available. The maximum is 1360x768.

Since the internal LVDS has a native resolution of 1200x800, he needs to add
 SubSection "Display"
  Virtual 1680 1200
to the "Screen" section of xorg.conf in order to get the higher resolution even with the 2.4 driver.

00:00.0 Host bridge [0600]: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub [8086:27a0] (rev 03)
 Subsystem: Sony Corporation Device [104d:81e6]
00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller [8086:27a2] (rev 03)
 Subsystem: Sony Corporation Device [104d:81e6]

System environment:
-- chipset: 945GM
-- system architecture: 32-bit
-- xf86-video-intel: 2.6.3 and 2.7.99
-- xserver: (1.6.2 RC 1)
-- kernel: Linux ubuntu 2.6.30-8-generic #9-Ubuntu SMP
-- Linux distribution: Ubuntu
-- Machine or mobo model: Sony VAIO vgn-szlm
-- Display connector: VGA

Xorg-log from ubuntu 9.04 with driver version 2.4 installed:
Output of `xrandr --verbose` with driver version 2.4:
Xorg-log from ubuntu 9.10 which has driver version 2.7.99:
Output of `xrandr --verbose` with driver version 2.7.99:
Comment 1 Geir Ove Myhr 2009-06-25 02:30:06 UTC
I should add that while the 2.4 logs says that the driver version is 2.4.1, there are quite a number of patches from 2.4.x making it closer to 2.4.3 in practice:
Comment 2 MaLing 2009-06-28 18:55:06 UTC
hi Geir
The root cause is your monitor is Digital monitor and not real analog display VGA.
II) intel(0): EDID Version: 1.3
II) intel(0): Digital Display Input

In our latest driver we guarantee monitor connected with VGA must be analog output by if (!edid_mon || DIGITAL(edid_mon->features.input_type) sentence.
Your monitor is pluged by DVI-I VGA convert as bug #21632?
Ma Ling

Comment 3 MaLing 2009-06-30 02:14:43 UTC

16:10 Aspect Ratio 
3000:1 Contrast Ratio 
160/160 Degree Viewing Angle 
Digital Comb Filter 
1440x900 Panel Resolution (Pixels) 
5 (ms) Screen Response Rate 
HD Ready 
1 x HDMI Connection 
1 x Component Video Connection 
1 x RS232 Connection 
1 x Standard Scart Connection 
1 x RGB Scart Connection 
1 x PC D-Sub Connection

From above message, I assume you connect VGA cable to PC D-Sub connection, so if yes, I close the issue, please contact vendor and ask them why D-Sub port will provide digital EDID not analog EDID. Pls open it if you need.

Ma Ling

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.