Bug 88947 - "Unknown" display appears with no external display connected
Summary: "Unknown" display appears with no external display connected
Status: NEW
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/nouveau (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Nouveau Project
QA Contact: Xorg Project Team
Depends on:
Reported: 2015-02-03 17:10 UTC by Anthony Wong
Modified: 2015-02-03 21:18 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


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Description Anthony Wong 2015-02-03 17:10:33 UTC
1. boot to desktop with no external monitor connected
2. Open the "Display" utility, check whether there is an "Unknown" display. You will be able to move the cursor out of your screen, even open an application on the extended display.

Tested with 2015-01-29 drm-intel-nightly.

00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0106] (rev 09) (prog-if 00 [VGA controller])
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF108M [GeForce GT 630M] [10de:0de9] (rev a1) (prog-if 00 [VGA controller])

Original bug: https://bugs.launchpad.net/ubuntu/+source/linux-lts-trusty/+bug/1355562
Comment 1 Alex Deucher 2015-02-03 21:18:32 UTC
I'm guessing this is a muxed hybrid laptop?  We hit a similar issue in radeon.  Basically the desktop environment doesn't understand muxed displays so it reports the status of both GPUs.  Arguably vgaswitcheroo needs to be augmented to properly report the mux information so userspace can do the right thing with respect to muxed laptops, but a short term fix would be to just report disconnected on whatever GPU is not currently selected via the mux.

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