External HDMI monitor failed to show screen on Lenovo X1 series

Bug #1738523 reported by AaronMa on 2017-12-16
This bug affects 1 person
Affects Status Importance Assigned to Milestone
HWE Next
linux (Ubuntu)
linux-oem (Ubuntu)

Bug Description

Thinkpad X1 yoga:
CPU: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz (family: 0x6, model: 0x8e, stepping: 0xa)
GPU: Intel Corporation Device [8086:5917] (rev 07) (prog-if 00 [VGA controller])

1, Connect an external monitor
2, Try to switch display modes in mirrored, extended, displayed on external or internal.

External HDMI monitor failed to show screen on Lenovo X1 yoga/carbon

Add a workaround to bypass this TMDS_OE writing on identified laptop models.

[Test Case]
Tested on ThinkPad X1 yoga 2nd/3rd and Carbon 6th, external HDMI output

[Regression Potential]
Low, it limits to ThinkPad specific laptops.

AaronMa (mapengyu) on 2017-12-16
tags: added: originate-from-1725109 sutton
AaronMa (mapengyu) on 2017-12-16
description: updated

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 1738523

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
Changed in linux (Ubuntu):
status: Incomplete → Triaged
importance: Undecided → Medium
Changed in hwe-next:
importance: Undecided → High
assignee: nobody → AaronMa (mapengyu)
AaronMa (mapengyu) on 2018-01-04
Changed in linux (Ubuntu):
assignee: nobody → AaronMa (mapengyu)
Seth Forshee (sforshee) on 2018-01-05
Changed in linux (Ubuntu):
status: Triaged → Fix Committed
Timo Aaltonen (tjaalton) wrote :

has this been sent upstream, or at least a bug?

AaronMa (mapengyu) wrote :

A request had been sent to Intel to make a better solution to solve this
issue. This patch is a WA before Intel fix it.
So this patch will not be going upstream.

Upstream bug: https://bugs.freedesktop.org/show_bug.cgi?id=100226

Changed in linux-oem (Ubuntu Xenial):
status: New → Fix Committed
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