Public bug reported:
The graphics system fails to detect monitors connected to ports on
docking stations. The ports themselves are detected an reported, but
stay in state "disconnected" regardless there are monitors connected or
not.
Internally the laptop has two Display-Ports, two HDMI-Ports and the build in
Display. xrandr reports them:
- eDP-1 (Internal display)
- DP-1 (Internal Display-Port-1)
- DP-2 (Internal Display-Port-2)
- HDMI-1 (Internal HDMI-Port-1)
- HDMI-2 (Internal HDMI-Port-2)
Two of the four ports are wired to the laptop hardware-ports
- DP-1 -> Mini-Display-Port
- HDMI-1 -> HDMI-Port
Within the docking station there are additional hardware ports wired:
- HDMI-1 -> VGA
- DP-1 -> DVI
- DP-1 -> Display-Port-1
- HDMI-2 -> HDMI
- DP-2 -> Display-Port-2
Connecting displays to any of these ports is reported running Windows
10, or Ubuntu 21.04. With Ubuntu 21.10 only displays connected to the
Mini-Display-Port are reported. All other hardware ports are ignored and
will stay in disconnected state, even if active monitors are connected
to them.
This is what xrandr reports if two monitors are connected directly to the
laptop, one via HDMI, the other via Mini-Display-Port:
eDP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 308mm
x 173mm
1920x1080 60.01*+ 60.01 59.97 59.96 59.93
[...]
360x202 59.51 59.13
320x180 59.84 59.32
DP-1 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis)
520mm x 330mm
1920x1200 59.95*+
[...]
640x480 75.00 59.94
720x400 70.08
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected (normal left inverted right x axis y axis)
The monitors connected to the build in HDMI are not recognized, as those
connected to both Display-Ports available on this dock.
Connecting monitors only to the Dock only the build in display is
recognized, no other.
Seen this on:
- ThinkPad T450s (20BW)
- ThinkPad T460s (20FA)
- ThinkPad T470s (20HF, 20HG)
With ThinkPad Ultra Dock (40A2)
Then:
- ThinkPad T480
- ThinkPad T490
- ThinkPad T14
With ThinkPad Ultra Dock (40AJ)
Same Problem exists with
- Acer TravelMate and Acer-Dock II
- Dell and Dell-Docks
The bug might be within the kernel, graphics subsystems, x11, wayland.
I could verity that going back to Ubuntu 21.04 (hirsute) this bug vanishes. And
starts showing up again after upgrading to 21.10 (impish).
ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: libxrandr2 2:1.5.2-0ubuntu1
ProcVersionSignature: Ubuntu 5.13.0-21.21-generic 5.13.18
Uname: Linux 5.13.0-21-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: pass
CompositorRunning: None
Date: Thu Dec 23 10:20:55 2021
DistUpgraded: Fresh install
DistroCodename: impish
DistroVariant: ubuntu
GraphicsCard:
Intel Corporation Skylake GT2 [HD Graphics 520] [8086:1916] (rev 07) (prog-if
00 [VGA controller])
Subsystem: Lenovo Skylake GT2 [HD Graphics 520] [17aa:2233]
InstallationDate: Installed on 2021-08-18 (127 days ago)
InstallationMedia: Xubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
MachineType: LENOVO 20FAS16K00
ProcKernelCmdLine: BOOT_IMAGE=/BOOT/ubuntu_sxscpx@/vmlinuz-5.13.0-21-generic
root=ZFS=rpool/ROOT/ubuntu_sxscpx ro quiet splash vt.handoff=1
SourcePackage: libxrandr
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/30/2016
dmi.bios.release: 1.20
dmi.bios.vendor: LENOVO
dmi.bios.version: N1CET52W (1.20 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20FAS16K00
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.9
dmi.modalias:
dmi:bvnLENOVO:bvrN1CET52W(1.20):bd11/30/2016:br1.20:efr1.9:svnLENOVO:pn20FAS16K00:pvrThinkPadT460s:rvnLENOVO:rn20FAS16K00:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_20FA_BU_Think_FM_ThinkPadT460s:
dmi.product.family: ThinkPad T460s
dmi.product.name: 20FAS16K00
dmi.product.sku: LENOVO_MT_20FA_BU_Think_FM_ThinkPad T460s
dmi.product.version: ThinkPad T460s
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.107-8ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.2.2-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.13-1ubuntu1.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2build1
version.xserver-xorg-video-intel: xserver-xorg-video-intel
2:2.99.917+git20200714-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-1build1
** Affects: ubuntu
Importance: Undecided
Status: New
** Tags: amd64 apport-bug impish ubuntu
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https://bugs.launchpad.net/bugs/1955636
Title:
Fails to detect monitors connected to docking stations
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