No image on KVM switch

Bug #1816269 reported by Stuart
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Incomplete
Undecided
Unassigned

Bug Description

Hi all,

I have a NUC7i7BNH with the latest BIOS (0062) running Ubuntu 18.04 (uname -r = 4.18.0-15-generic). I have the NUC connected via USB-C to a dual DisplayPort adapter, to an Avocent SV340D KVM.

If I have the KVM on the switch for the NUC, everything works great. If I switch the KVM to another channel, and then switch back to the NUC, I only get black screens. The only solution is to hard reboot the NUC.

Any help would be appreciated.

Tags: cosmic
Stuart (shutch)
description: updated
Revision history for this message
Stuart (shutch) wrote :

@Update: Disabling DP1.2 and DDC/CI on the monitors seems to solve this. The monitors are Dell U2415.

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Stuart (shutch) wrote :

@Update: cancel above comment, worked initially.

affects: xorg-server (Ubuntu) → linux (Ubuntu)
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Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote : Missing required logs.

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1816269

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
tags: added: cosmic
Revision history for this message
Kai-Heng Feng (kaihengfeng) wrote :

Would it be possible for you to test the latest upstream kernel? Refer
to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
v5.0-rc7 kernel[0].

If this bug is fixed in the mainline kernel, please add the following
tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag:
'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as
"Confirmed".

Thanks in advance.

[0] https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.0-rc7/

Revision history for this message
Stuart (shutch) wrote :

@Kai-Heng - thanks. Been testing 5.0-rc7 and seems to be working, but want to test it a few more days.

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Stuart (shutch) wrote :

@Kai-Heng seems to be working better (not 100%, but much better) using Wayland, but doesn't seem better on x11

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Kai-Heng Feng (kaihengfeng) wrote :

Please attach dmesg.

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Stuart (shutch) wrote :

See attached.

Currently getting flickering on one monitor.

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Kai-Heng Feng (kaihengfeng) wrote :

[ 135.089830] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
and then Thunderbolt hotplug messages.

Please file an upstream bug at https://bugs.freedesktop.org/
Product: DRI
Component: DRM/Intel

Revision history for this message
Stuart (shutch) wrote :
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