** Description changed: - Since linux-4.4.0-98, the kernel additionally load gcserial driver for + [Impact] + + * Dell Wireless DW5818/5819 modems showed an incorrect signal strength + and were using a ttyUSB* port for data connections instead of the MBIM + device (which provides better performance). + + Since linux-4.4.0-98, the kernel additionally loads gcserial driver for Dell Wireless DW5818/5819. The reason behind it is to support firmware - switching and upgrading. However, the change makes ModemManager to use - Gobi plugin for this two modules. With Gobi plugin, the modules could + switching and upgrading. However, the change makes ModemManager use Gobi + plugin for this two modules. With Gobi plugin, the modules could establish data links, but it failed to retrieve the signal state. And it caused the mmcli and nm-applet giving wrong signal strength. The modules support the MBIM protocol, so ModemManager should use Dell plugin for these two modules. I have worked out a patch to forbid these two modules in Gobi plugin, and it does work well. + + [Test Case] + + Current MM: + * Create connection with + $ nmcli c add type gsm ifname ttyUSB2 con-name gsmconn apn <operator APN> + * Without the patched package, mmcli shows, with an active connection (see comment #2): + primary port: 'ttyUSB2' + signal quality: '0' (recent) + + Patched MM: + * Create connection with + $ nmcli c add type gsm ifname cdc-wdm0 con-name gsmconn apn <operator APN> + * With the patched package, mmcli shows, with an active connection (see comment #7): + primary port: 'cdc-wdm0' + signal quality: '38' (cached) + + [Regression Potential] + + The patch simply adds the Sierra modems VID/PIDs to the list of + forbidden ids in the Gobi plugin, so the possibility of a regression is + very small: only products with said VID/PID will be affected.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1735134 Title: ModemManager uses a wrong plugin for Dell DW5818/5819 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/modemmanager/+bug/1735134/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
