Bug 21641

Summary: [915GM] no modes detected for LVDS
Product: xorg Reporter: Martin <martin1404>
Component: Driver/intelAssignee: MaLing <ling.ma>
Status: RESOLVED DUPLICATE QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: jbarnes, michael.fu
Version: unspecified   
Hardware: Other   
OS: All   
i915 platform: i915 features:
Description Flags
working xorg.conf
log of working status with latest driver 2.7.0
broken xorg.conf with modedebug on
log from broken configuration
rom none

Description Martin 2009-05-09 05:14:13 UTC
I would like to move upstream one bug I have encountered with Mandriva 2009.1 as it is clearly broken on other linux distros as well.

The original bug can be found here: https://qa.mandriva.com/show_bug.cgi?id=44787

I will try to quickly summarize it here.
Since version 2.4 of intel driver for xorg it stopped working on my laptop, which is ASUS M6A with intel 915 graphic chipset. The last known correctly working version of the driver is 2.2.1

The problem which occurs is that X will not start on this graphic chip using intel driver. Following error appears:

(EE) intel(0): Output LVDS enabled but has no modes
(EE) intel(0): No valid modes.
(EE) Screen(s) found, but none have a usable configuration.

This will not allow the x server start, which means no desktop environment for the user. It is very annoying, especially for linux first time users.

The last version of intel driver I tried was 2.7.99 or something. The problem persists. I have found a workaround for this problem but it is definitely not correct because of previously mentioned first time users. They simply do not know (and sometimes do not want to know) how to manually edit xorg.conf.

Also I think it is a regression, as it was working OK in older versions of intel driver.

The mentioned workaround is based on using Option "LVDSFixedMode" "false" driver option and editing xorg.conf:

Section "Monitor"
    Identifier "monitor1"
    VendorName "Generic"
    ModelName "Flat Panel 1280x800"
    ModeLine "1280x800_60"  83.46  1280 1344 1480 1680  800 801 804 828 -HSync
    Option "PreferredMode" "1280x800_60"

The configuration will not work without the correct ModeLine and the Option "PreferredMode".

I am succesfully using this workaround on the 2.7.0 version of intel driver and it also works on 2.7.99

If you need more info, you can find a lot of it in the above mentioned Mandriva bug and of course I am ready to help you testing repaired versions of the driver ;-)
Comment 1 MaLing 2009-05-11 00:20:54 UTC
plese refer to http://intellinuxgraphics.org/how_to_report_bug.html and provide log file with modedebug option on.

Comment 2 Michael Fu 2009-05-11 01:07:49 UTC
Martin, we need at least a xorg.log of running latest 2.7.0 driver, with modedebug turns on. 
Comment 3 Martin 2009-05-11 01:42:37 UTC
Created attachment 25723 [details]
working xorg.conf
Comment 4 Martin 2009-05-11 01:43:15 UTC
Created attachment 25724 [details]
log of working status with latest driver 2.7.0
Comment 5 Michael Fu 2009-05-11 06:31:15 UTC
(In reply to comment #3)
> Created an attachment (id=25723) [details]
> working xorg.conf

please only keep the modedebug option and get rid of others, then submit the log.
Comment 6 Martin 2009-05-11 10:14:37 UTC
Created attachment 25740 [details]
broken xorg.conf with modedebug on
Comment 7 Martin 2009-05-11 10:15:10 UTC
Created attachment 25741 [details]
log from broken configuration
Comment 8 Michael Fu 2009-05-11 16:33:57 UTC
# cd /sys/devices/pci0000\:00/0000\:00\:02.0/
# echo 1 > rom
# cat rom > /tmp/rom.bin
# echo 0 > rom

please attach your rom.bin via above command. thanks.
Comment 9 Martin 2009-05-11 21:30:03 UTC
Created attachment 25783 [details]

Here it is
Comment 10 Michael Fu 2009-05-12 00:03:17 UTC
studied the VBT in the rom. Same bug as bug# 19460 - the pointers in block# 41 of VBT is busted...should be fixed by the patch in bug# 19460 comment# 45 .. 

copying Jesse.

*** This bug has been marked as a duplicate of bug 19460 ***

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