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dmi_dmi_dmi

Member

Registered: 2021-08-03

Posts: 4

Too many change events in udevadm monitor

I am using Asus ROG G14 laptop (G401IH model, quite similar to this) with 5.14.8-arch1-1 kernel.

Yesterday I tried to debug connection issues for custom made USB device. I launched `udevadm monitor` for that purpose and immediately noticed that the kernel produces tons of events for type-c (basically every second comes a couple of events). Nothing is plugged in into the port though.

I am seeing this

> sudo udevadm monitor -k
[sudo] password for dmi: 
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[61712.356028] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61712.755785] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61712.965369] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61713.272405] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61713.469006] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61713.675436] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61713.979006] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61714.292046] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61714.906012] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61715.112638] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61715.505529] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61715.899145] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61716.218967] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61716.322544] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61716.522493] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61716.915887] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61717.115351] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61718.605788] change   /devices/platform/USBC000:00/typec/port0 (typec)
KERNEL[61718.809000] change   /devices/platform/USBC000:00/typec/port0 (typec)
^C

~ took 12s 
> 

Frequency of events bother me a lot. Is this normal for laptops with type c ports to generate so many events? If no how would one debug (reading material, tools, tips and tricks) what causes the problem?

Last edited by dmi_dmi_dmi (2021-10-04 15:53:09)