two MST display detected as one /dev/i2c device

Bug #2019174 reported by ntz
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
i2c-tools (Ubuntu)
New
Undecided
Unassigned

Bug Description

using a laptop with a thunderbolt connection, and a TB docking station.
Two monitors connected to the docking station (via DisplayPort and HDMI), but only one display is detected as a i2c-device.
the laptop is ASUS made, with Intel i7-12700H CPU. seems to be Intel/i915. graphics issue.
the models are Hyundai X93W (monitor), LG 27BN65Q (monitor), ASUS SimPro Dock 2 (Thunderbolt Dock) and ASUS TP3402ZA (laptop)

i2c outputs:

❯ ls /sys/bus/i2c/devices/i2c*/name | xargs grep ".*"
/sys/bus/i2c/devices/i2c-0/name:SMBus I801 adapter at efa0
/sys/bus/i2c/devices/i2c-10/name:i915 gmbus tc4
/sys/bus/i2c/devices/i2c-11/name:i915 gmbus tc5
/sys/bus/i2c/devices/i2c-12/name:i915 gmbus tc6
/sys/bus/i2c/devices/i2c-13/name:AUX A/DDI A/PHY A
/sys/bus/i2c/devices/i2c-14/name:AUX USBC1/DDI TC1/PHY TC1
/sys/bus/i2c/devices/i2c-15/name:AUX USBC2/DDI TC2/PHY TC2
/sys/bus/i2c/devices/i2c-16/name:AUX USBC3/DDI TC3/PHY TC3
/sys/bus/i2c/devices/i2c-17/name:AUX USBC4/DDI TC4/PHY TC4
/sys/bus/i2c/devices/i2c-18/name:DPMST
/sys/bus/i2c/devices/i2c-19/name:DPMST
/sys/bus/i2c/devices/i2c-1/name:Synopsys DesignWare I2C adapter
/sys/bus/i2c/devices/i2c-2/name:Synopsys DesignWare I2C adapter
/sys/bus/i2c/devices/i2c-3/name:Synopsys DesignWare I2C adapter
/sys/bus/i2c/devices/i2c-4/name:i915 gmbus dpa
/sys/bus/i2c/devices/i2c-5/name:i915 gmbus dpb
/sys/bus/i2c/devices/i2c-6/name:i915 gmbus dpc
/sys/bus/i2c/devices/i2c-7/name:i915 gmbus tc1
/sys/bus/i2c/devices/i2c-8/name:i915 gmbus tc2
/sys/bus/i2c/devices/i2c-9/name:i915 gmbus tc3
/sys/bus/i2c/devices/i2c-ASUE140D:00/name:ASUE140D:00
/sys/bus/i2c/devices/i2c-WDHT1F01:00/name:WDHT1F01:00

❯ i2cdetect -y 18
     0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

❯ i2cdetect -y 19
     0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

❯ i2cdetect -y 14
     0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: 30 -- -- -- -- 35 -- 37 -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- 4a 4b -- -- -- --
50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: i2c-tools 4.3-2build1
Uname: Linux 6.2.8-060208-generic x86_64
NonfreeKernelModules: tuxedo_keyboard
ApportVersion: 2.23.1-0ubuntu3.2
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu May 11 09:12:56 2023
InstallationDate: Installed on 2023-03-24 (47 days ago)
InstallationMedia: Ubuntu 22.10 "Kinetic Kudu" - Release amd64 (20221020)
SourcePackage: i2c-tools
UpgradeStatus: No upgrade log present (probably fresh install)

Revision history for this message
ntz (ntz1) wrote :
ntz (ntz1)
description: updated
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