I never saw a response on this question, but I finally figured out -- with some assistance from a Quectel engineer -- that the error is a kernel error related to USB communication with the modem as everything is being shut down for the reboot, and that ModemManager has no direct link to the issue. I've made a tiny kernel patch that seems to resolve the problem and have sent it to Quectel for consideration.
Bruce Johnson Chantilly, Virginia USA On 26/08/2024 11:52, Bruce Johnson wrote: > I am getting a kernel message spew on the console whenever I reboot > one of my boxes that's equipped with a Quectel EG25-G modem: > >> option1 ttyUSB0: usb_wwan_write: submit urb 0 failed: -19 > > When this happens, the reboot either does not complete or takes so > long that it is unacceptable. It happens after the system has closed > systemd-journald, so I haven't yet been able to find any additional > information that might help. > > If I stop ModemManager for a little while before issuing the reboot, > this doesn't happen. I've tried juggling the shutdown order and timing > of the relevant systemd services but haven't yet found a way to put in > sufficient delay for a reboot to occur reliably. > > My team is currently upgrading our project from Yocto's Dunfell branch > to their Scarthgap branch. This takes us from Linux kernel 5.4.34 to > 6.6.23, and from ModemManager 1.18.4 to 1.22. Everything worked great > in the old setup. > > I'm not well acquainted with either body of source code (ModemManager > or Linux kernel). Can anyone advise me on how I might be able to > figure this out? >
