Bug 735536

Summary: [Cantiga] Wrong monitor detection with Intel GM45 chipset
Product: [Fedora] Fedora Reporter: Franco Bugnano <fri8k>
Component: xorg-x11-drv-intelAssignee: Adam Jackson <ajax>
Status: CLOSED CANTFIX QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 15CC: ajax, mcepl, xgl-maint
Target Milestone: ---Keywords: Triaged
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard: [cat:rendering]
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-10-13 14:13:08 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
Xorg log file of the Fedora 15 Live session
none
/var/log/messages of the Fedora 15 Live session
none
dmesg output of the Fedora 15 Live session
none
Xorg log file of the Fedora 14 Live session
none
/var/log/messages of the Fedora 14 Live session
none
dmesg output of the Fedora 14 Live session none

Description Franco Bugnano 2011-09-03 07:52:24 UTC 
Description of problem:
I have an AOpen MP45-DR PC, which is a desktop PC with the mobile version of the GM45 chipset.
Being a desktop PC, the only monitor connected to it is the one connected to the DVI port.

In Fedora 15 (and 16 Alpha) the driver sees that the chipset is a mobile one, so it thinks it is a Laptop, and it detects 2 monitors:
1. Laptop
2. The monitor connected to the DVI port.
And it sets the non existent Laptop monitor as the primary one.

As a consequence, I cannot login to gdm, because the login screen is shown on the non existent monitor.

This bug was there also in the Fedora 11 release, but got fixed in the Fedora 12 Alpha, and it worked well up to Fedora 14.



How reproducible:
Always

Steps to Reproduce:
1. Power On
  
Actual results:
The only thing that is seen on the only monitor connected to the PC is the gdm background, as the driver thinks it is the secondary monitor.

Expected results:
The driver correctly detects that there is only one monitor connected to the PC, and it uses it as the primary (and only) monitor.
Comment 1 Matěj Cepl 2011-09-04 00:33:38 UTC 
Thanks for the bug report.  We have reviewed the information you have provided above, and there is some additional information we require that will be helpful in our diagnosis of this issue.

Please add drm.debug=0x04 to the kernel command line, restart computer, and attach

* your X server config file (/etc/X11/xorg.conf, if available),
* X server log file (/var/log/Xorg.*.log*; check with grep Backtrace /var/log/Xorg* which logs might be the most interesting ones, send us at least Xorg.0.log)
* output of the dmesg command, and
* system log (/var/log/messages)

to the bug report as individual uncompressed file attachments using the bugzilla file attachment link above.

We will review this issue again once you've had a chance to attach this information.

Thanks in advance.
Comment 2 Franco Bugnano 2011-09-05 18:47:58 UTC 
Created attachment 521533 [details]
Xorg log file of the Fedora 15 Live session
Comment 3 Franco Bugnano 2011-09-05 18:49:26 UTC 
Created attachment 521534 [details]
/var/log/messages of the Fedora 15 Live session
Comment 4 Franco Bugnano 2011-09-05 18:50:00 UTC 
Created attachment 521535 [details]
dmesg output of the Fedora 15 Live session
Comment 5 Franco Bugnano 2011-09-05 19:05:32 UTC 
Created attachment 521539 [details]
Xorg log file of the Fedora 14 Live session
Comment 6 Franco Bugnano 2011-09-05 19:06:04 UTC 
Created attachment 521540 [details]
/var/log/messages of the Fedora 14 Live session
Comment 7 Franco Bugnano 2011-09-05 19:06:37 UTC 
Created attachment 521542 [details]
dmesg output of the Fedora 14 Live session
Comment 8 Franco Bugnano 2011-09-05 19:07:25 UTC 
Ok, I have attached both the non working Fedora 15 files and the working Fedora 14 files for comparison
Comment 9 Adam Jackson 2011-10-13 14:13:08 UTC 
Nothing we can really do about this, Intel doesn't have any way of reliably detecting whether LVDS or eDP is attached so we have to assume it is.  We keep looking for reliable heuristics and they keep not working.

Workaround is to boot with 'video=LVDS-1:d' on the kernel command line to disable the phantom LVDS output.
Comment 10 Franco Bugnano 2011-10-15 18:39:02 UTC 
The workaround works like a charm, thank you very much.

I propose to document both this bug and its workaround in the list of known bugs.