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sim-mbim: increase the timeout for the MBIM_CID_HOME_PROVIDER query

Vincent Palatin requested to merge vpalatin/ModemManager:home_provider_timeout into master

Increase the timeout from 10 seconds to 30 seconds when reading the operator information through the MBIM_CID_HOME_PROVIDER query. We have observed cases where it took more than 12 seconds on a Fibocom L850-GL modem with specific China Unicom SIMs.

This timeout was actually the cause of a corruption of the operator name (e.g. returning '@' rather than the real operator name) on the Intel XMM7360 based L850-GL. The following scenario was happening:

  • the base-sim code sends a first MBIM 'home-provider' query to read the operator identifier.
  • this query times-out after 10 seconds.
  • the base-sim immediately sends another MBIM 'home-provider' query to read the operator name.
  • the modem returns a corrupted operator identifier.

Intel helped for the debugging and indicates that when the first query happens, the modem starts reading the SIM files (EF SPN/PNN), apparently it's taking a long time, when it's receives the second query while the first one is not entirely processed, this triggers a bug (in the modem firmware) and returns a corrupted name.

Edited by Vincent Palatin

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