MC7304 No response from SLQSStartStopDataSession


I am using MC7304 / Linux QMI SDK version SLQS03.03.17
During connection/dysconnection tests on my target, my modem sometimes seems to be blocked while reconnecting.
After being attached on public APN, SLQSStartStopDataSession() does not answer, timeout fire 2mn later.
System log are:

wdsSMprint/179: action: START, sid: 0, v4sid: 0, v6sid: 0
qaWdsSMprintSlots/164: V4 FSLOT: 0, V6 FSLOT: 0, V4V6 FSLOT: 0
wdsSessionDataLog/144: PDP0: v4SH: 0, v6SH: 0
wdsSessionDataLog/144: PDP1: v4SH: 0, v6SH: 0Sierra MC7304
wdsSessionDataLog/144: PDP2: v4SH: 0, v6SH: 0
wdsSMprint/195: - - - - - - - - - - - - - - - - - - - - - - - - - - -

Note that connection is working perfectly in most of case.

Any ideas ?

driver QMI version S2.25N2.34


I’d suggest to upgrade everything to the latest. modem FW, SDK, driver


Folowing components have been updated to latest version:
SDK SLQS04.00.16
driver S2.34N2.53
firmware SWI9X15C_05.05.78.00

I then have a new problem during startup : while modem is attached/connected and an IPv4 address has been affected on my interface (read from API SLQSGetRuntimeSettings), no interface is detected from my connection manager.
Interface associated eth2 is seen as “NO CARRIER”

ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
link/ether 00:80:97:09:ed:20 brd ff:ff:ff:ff:ff:ff
3: eth1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000
link/ether 00:80:97:09:ed:24 brd ff:ff:ff:ff:ff:ff
4: tunl0: mtu 0 qdisc noop state DOWN mode DEFAULT
link/ipip brd
5: gre0: mtu 1476 qdisc noop state DOWN mode DEFAULT
link/gre brd
6: gretap0: <BROADCAST,MULTICAST> mtu 1476 qdisc noop state DOWN mode DEFAULT qlen 1000
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
7: wifi: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
link/ether 00:0e:8e:50:b9:ba brd ff:ff:ff:ff:ff:ff

18: eth2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000
link/ether 0e:50:29:f2:d1:08 brd ff:ff:ff:ff:ff:ff

What’s wrong ?


Hi Bruno,

It is possible that modem manager tries to access the modem, try to disable it.
Sierra’s connection manager sample app. brings up the session (between the modem & host) with startstopdatasession() call.
does this call returns with an error?

if the call returns with 0 - success then the next step is to call dhcp - most PCs launch this aromatically.



Hello James,
Thank you for your answer.
My modem manager (Ofono) was already disconnected from Sierra modem.
Return code comming from my from SDK is 15 (timeout 2mn), the problem is then that any additional call seems to be locked.
The solution to my pb consisted to update Ofono, including MC7304 Sierra modem management, and qmi driver included in OS Linux.
It seems to work properly.