MC7455 in X220 with ModemManager 1.6.4

[Aleksander Morgado]

Hey,

Sorry it took so long to reply; looks like I lost this email in my inbox. I'm breaking threading as well here, sorry.

> I did recently change modem in my Lenovo X220 running Ubuntu 16.04 to MC7455 I bought from Farnell. I did add Aleksander PPA for ModemManager on Xenial: https://launchpad.net/~aleksander-m to get newer version on MM, which should hopefully support my modem. Unfortunately I found that bug which prevents MM sending FCC auth for MC7455 is still included in code in MM 1.6.4 release:
> 
> https://cgit.freedesktop.org/ModemManager/ModemManager/commit/?id=21f315f6d554b93e4f098cfd0e94c484a8a0c5dc
> 
> I tried to backport given fix into MM source package for 1.6.4 on PPA but even I did so, I am not able to correctly pass FCC auth ( whole MM debug
> is attached). May I please kindly ask Aleksander, would it be possible to update your PPA to MM 1.6.6 so I can try my modem with latest MM version? (maybe there is something else needed to get my modem to work correctly) Thank you so much.
> 

I don't think FCC auth is your problem, you're getting a "NoEffect" error and that means there is no need to send FCC auth:
ModemManager[2748]: <debug> [1496072816.201321] [mm-broadband-modem-qmi.c:3024] dms_set_fcc_authentication_ready(): Couldn't set FCC authentication: QMI protocol error (26): 'NoEffect'


> - I used Sierra flash tool under windows to flash latest FW and install drivers under Windows7 as I read some reports about images problem with card but without any efect.
> 

Oh, you should have used qmi-firmware-update, it works very well ;)

> - To get MC7455 working in X220 miniPCIe slot I used whitelist BIOS and I need to isolate some pins on card: odd pins 1-51 (whole top side) and pins 30, 32. (So in fact only USB2, SIM interface and WWAN LED pins are connected) I did not isolate PIN 20 for rfkill, but modem is not even visible under rfkill list all.
> 

Oh, hum. See, there you may have a problem. When we query the "operating mode" from the device, it is telling us that it is in "low-power" mode due to "hardware restricted mode". Maybe you do need to play with the rfkill pins as well?

<<<<<< QMI:
<<<<<<   flags       = "response"
<<<<<<   transaction = 20
<<<<<<   tlv_length  = 15
<<<<<<   message     = "Get Operating Mode" (0x002D)
<<<<<< TLV:
<<<<<<   type       = "Result" (0x02)
<<<<<<   length     = 4
<<<<<<   value      = 00:00:00:00
<<<<<<   translated = SUCCESS
<<<<<< TLV:
<<<<<<   type       = "Mode" (0x01)
<<<<<<   length     = 1
<<<<<<   value      = 01
<<<<<<   translated = low-power
<<<<<< TLV:
<<<<<<   type       = "Hardware Restricted Mode" (0x11)
<<<<<<   length     = 1
<<<<<<   value      = 01
<<<<<<   translated = yes


> - Under Ubunutu NetworkManager, I had 'Enabled Mobile Broadband' *card) but I can not enable the connection - as it is greyed out. Which is probably consequence of modem never reports operation state, being in low power mode - see the log.

Unfortunately, fixing the low-power issue won't be the only problem if you want to run the modem in QMI mode. The MC7455 requires "raw-ip" support in the Linux kernel qmi_wwan driver, and the default kernel version coming in Ubuntu 16.04 is not new enough. I did prepre an additional PPA to include Linux 4.4 in Ubuntu 16.04, but note that I'm really not maintaining that one actively:
https://launchpad.net/~aleksander-m/+archive/ubuntu/kernel-xenial-qmi-raw-ip

If you want to skip the kernel problem, you may want to switch the modem into MBIM mode; although I don't recall if there were missing MBIM fixes that would be required for this device in Linux 4.3; but worth testing (once you fix the low-power mode issue).

Or just switch to a newer Ubuntu version... :)

-- 
Aleksander
https://aleksander.es