Bug 25471 - [945GM] attaching external VGA disables LVDS
Summary: [945GM] attaching external VGA disables LVDS
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: Jesse Barnes
QA Contact:
Keywords: NEEDINFO
Depends on:
Reported: 2009-12-06 01:05 UTC by Anton Khirnov
Modified: 2017-07-24 23:09 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

patch fixing this issue (863 bytes, patch)
2010-02-28 04:05 UTC, Anton Khirnov
no flags Details | Splinter Review

Description Anton Khirnov 2009-12-06 01:05:55 UTC
If i attach an external VGA monitor to my laptop with 945GM *after* X has started and run xrandr, internal LVDS immediately switches off, with xrandr saying "LVDS1 disconnected". This doesn't happen if i connect external VGA before starting X.

This issue happens with kernels 2.6.32-rc1 and later, doesn't happen with
Comment 1 Jesse Barnes 2010-02-05 14:47:08 UTC
Still happen with current kernels?
Comment 2 Jesse Barnes 2010-02-11 10:44:59 UTC
Also note some distributions have an X that listens for hotplug events, so it could be that your desktop is reconfiguring your system when you plug in the VGA (though LVDS definitely shouldn't be marked as "disconnected" at that time).

What does /proc/acpi/button/lid/LID/state report after you plug in VGA?
Comment 3 Anton Khirnov 2010-02-28 04:04:40 UTC
(In reply to comment #2)
> What does /proc/acpi/button/lid/LID/state report after you plug in VGA?
This was right on -- after I close the lid once it reports its state as closed even after I open it.

Blacklisting my laptop fixes the issue for me. Patch attached.
Comment 4 Anton Khirnov 2010-02-28 04:05:56 UTC
Created attachment 33638 [details] [review]
patch fixing this issue
Comment 5 Jesse Barnes 2010-02-28 12:27:35 UTC
Nice.  Can you send the patch to intel-gfx@lists.freedesktop.org (cc eric@anholt.net) and add a signed-off-by line?  Then we can close this one out.

Comment 6 Anton Khirnov 2010-03-14 23:24:43 UTC
So i sent the patch ~two weeks ago. When is something going to happen?
Comment 7 Jesse Barnes 2010-06-01 12:15:07 UTC
Thanks Anton, we ended up just removing the lid state checking since so many machines were broken.

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