Archer c2600 QMI LTE Sierra MC7455 Modem Help

Installing and Using OpenWrt Network and Wireless Configuration
#1

Hello!

I am following the instructions laid out here:
https://wiki.openwrt.org/doc/recipes/ltedongle#troubleshooting

In an attempt to get my Sierra MC7455 to make friends with my TP-Link Archer c2600 in QMI mode.

There has only been on irregular thing for this setup:

Kmod-usb-net-qmi-wwan package is for a later kernel I believe than what the Archer Lede Firmware has... so I had to force install it.

Anyway, I get to step 3 and use: cat /sys/kernel/debug/usb/devices

Which returns the following:

T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  5 Spd=480  MxCh= 0
D:  Ver= 2.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1199 ProdID=9071 Rev= 0.06
S:  Manufacturer=Sierra Wireless, Incorporated
S:  Product=Sierra Wireless MC7455 Qualcomm® Snapdragon™ X7 LTE-A
S:  SerialNumber=LQ72769427011020
C:* #Ifs= 4 Cfg#= 1 Atr=a0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=qcserial **Should be option**
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=qcserial **should be qmi_wwan**
E:  Ad=83(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=qcserial **should be qmi_wwan**
E:  Ad=85(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 8 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
E:  Ad=87(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
E:  Ad=86(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

For comparison, here is the result from the guide:

T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=480  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=12d1 ProdID=1506 Rev= 0.00
S:  Manufacturer=Huawei Technologies
S:  Product=HUAWEI Mobile
C:* #Ifs= 3 Cfg#= 1 Atr=c0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=01 Prot=02 Driver=option
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
I:* If#= 1 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=01 Prot=09 Driver=qmi_wwan
E:  Ad=82(I) Atr=03(Int.) MxPS=  64 Ivl=2ms
I:* If#= 2 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=01 Prot=08 Driver=qmi_wwan
E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms

The guide then goes on to describe the configuration process. If someone could help me out with the qmi_wwan driver stuff and any other things you run across, I would love that! I think I can figure out how to configure using UCI?

Should it look something like this?

uci del network.wan
uci set network.wan=interface
uci set network.wan.proto=qmi
uci set network.wan.device=/dev/cdc-wdm0
uci set network.wan.apn=r.ispsn
uci set network.wan.username= (do I need to populate anything here?)
uci set network.wan.password=(or Here)
uci commit network
reboot

Thanks to whomsoever helps :slight_smile:

#2

This looks correct to me. The 3 first USB interfaces are serial functions (DIAG, NMEA and MODEM). These are handled by the qcserial driver, as they should be.

The last interface here is QMI. Sierra use static interface numbers to identify different verndor specific functions. Interface number 8 will always be QMI. But the MC7455 supports only "raw-ip" framing and the qmi_wwan driver in Linux v4.4 supports only "802.3" framing. So the driver doesn't bind to this interface to avoid any confusion caused by a non-functional network device.

You can either wait for a new release with a newer kernel ("raw-ip" mode was added in Linux v4.5), or see if the proposed backport to LEDE-17.01 is merged: https://www.mail-archive.com/lede-dev@lists.infradead.org/msg11170.html

Or you can use the modem as an AT controlled PPP device in the meantime. That should work.