mbim-proxy uses 100% cpu with Sierra EM7345 LTE modem, unable to connect

[Jay Banyer]

I have a Sierra EM7345 LTE modem in a Lenovo T450s.

On boot mbim-proxy is using 100% cpu and the modem will not move to the connected state.

I have to kill the mbim-proxy process to stop it using CPU, and I can't get the modem to connect at all.

These bugs are probably related:

https://bugs.freedesktop.org/show_bug.cgi?id=100938

https://bugs.freedesktop.org/show_bug.cgi?id=101275

The problem also occurs with Ubuntu 17.04 run from a live USB stick.

I've used this exact hardware with several previous installs of Ubuntu and never had this problem.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: libmbim-proxy 1.12.2-2ubuntu1
ProcVersionSignature: Ubuntu 4.10.0-33.37~16.04.1-generic 4.10.17
Uname: Linux 4.10.0-33-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Aug 30 22:24:33 2017
InstallationDate: Installed on 2017-08-30 (0 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
SourcePackage: libmbim
UpgradeStatus: No upgrade log present (probably fresh install)

[Jay Banyer (jbanyer)]

Note: this problem occurs on every boot up.

I tried upgrading to mainline kernel 4.12.10 and the problem still occurs.

Not sure if it matters: I was running Ubuntu previously on this hardware without this issue. I recently installed Windows 10 on this machine and successfully used the Sierra LTE modem from that OS. Then I installed Ubuntu and this problem happens every time.

Thanks for looking into it.

[Jay Banyer (jbanyer)]

Note: this problem also happens with a Fedora 26 live CD.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.