SIM7600E time out while sending SMS
We have a SIM7600E which is sometimes the modem is very slow to send an SMS. When this happens there is a timeout in ModemManager (see the log below) and the modem is "completely disposed". This means it drops the perfectly working network connection and it doesn't restart by itself.
(Usually sending an SMS works fine; this is more easily triggered when using a particular international roaming SIM.)
Is it a simple matter of increasing a timeout for the AT+CMGS response, or is the timeout triggered by the other failing AT commands which are issued concurrently? Also, shouldn't ModemManager avoid sending other AT commands while the AT+CMGS command's OK/ERROR is pending?
<debug> [1561707204.191547] Processing chunk '0' of text with '10' bytes
<debug> [1561707204.191793] Created SMS part for singlepart SMS
<debug> [1561707204.191885] Creating PDU for part...
<debug> [1561707204.191937] requesting delivery report...
<debug> [1561707204.191987] using GSM7 encoding...
<debug> [1561707204.192174] user data length is '10' septets (without UDH)
<debug> [1561707204.192354] (ttyUSB3) device open count is 2 (open)
<debug> [1561707204.192676] (ttyUSB3): --> 'AT+CMGS=22<CR>'
<debug> [1561707204.207212] (ttyUSB3): <-- '<CR><LF>> '
<debug> [1561707204.207562] (ttyUSB3) device open count is 3 (open)
<debug> [1561707204.207695] (ttyUSB3) device open count is 2 (close)
<debug> [1561707204.207841] (ttyUSB3): --> '0021000B9164xxxxxxxxFx00000AEDF6989D06D1CB733A\26'
<debug> [1561707204.261028] (ttyUSB3): <-- '<CR><LF>'
<debug> [1561707205.197464] (ttyUSB3) device open count is 3 (open)
<debug> [1561707207.197763] loading signal quality...
<debug> [1561707207.197990] (ttyUSB3) device open count is 4 (open)
<debug> [1561707210.199337] (ttyUSB3) device open count is 5 (open)
<debug> [1561707214.197198] (ttyUSB3) device open count is 4 (close)
<debug> [1561707214.197443] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707215.196530] (ttyUSB3) device open count is 5 (open)
<warn> [1561707217.196750] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707217.196928] (ttyUSB3) device open count is 4 (close)
<warn> [1561707217.197065] (tty/ttyUSB3) at port timed out 2 consecutive times
<debug> [1561707217.197187] (ttyUSB3): --> 'AT+CIND?<CR>'
<debug> [1561707220.198180] (ttyUSB3) device open count is 5 (open)
<debug> [1561707222.196792] (ttyUSB3) device open count is 6 (open)
<debug> [1561707222.196983] (ttyUSB3) device open count is 5 (close)
<warn> [1561707222.197125] (tty/ttyUSB3) at port timed out 3 consecutive times
<debug> [1561707222.197257] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707225.198384] (ttyUSB3) device open count is 6 (open)
<warn> [1561707225.198616] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707225.198703] (ttyUSB3) device open count is 5 (close)
<warn> [1561707225.198814] (tty/ttyUSB3) at port timed out 4 consecutive times
<debug> [1561707225.199437] (ttyUSB3): --> 'AT+CGACT?<CR>'
<warn> [1561707228.196747] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707228.196915] (ttyUSB3) device open count is 4 (close)
<warn> [1561707228.197050] (tty/ttyUSB3) at port timed out 5 consecutive times
<debug> [1561707228.197175] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707230.197709] (ttyUSB3) device open count is 5 (open)
<warn> [1561707231.197089] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707231.197256] (ttyUSB3) device open count is 4 (close)
<warn> [1561707231.197387] (tty/ttyUSB3) at port timed out 6 consecutive times
<debug> [1561707231.197519] (ttyUSB3): --> 'AT+CSQ<CR>'
<debug> [1561707234.199671] Couldn't refresh signal quality: 'Serial command timed out'
<debug> [1561707234.199897] (ttyUSB3) device open count is 5 (open)
<debug> [1561707234.200038] (ttyUSB3) device open count is 4 (close)
<warn> [1561707234.200161] (tty/ttyUSB3) at port timed out 7 consecutive times
<debug> [1561707234.200291] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707235.197071] (ttyUSB3) device open count is 5 (open)
<debug> [1561707237.198460] Signal quality value not updated in 60s, marking as not being recent
<warn> [1561707237.198846] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707237.198949] (ttyUSB3) device open count is 4 (close)
<warn> [1561707237.199060] (tty/ttyUSB3) at port timed out 8 consecutive times
<debug> [1561707237.199636] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707240.198778] (ttyUSB3) device open count is 5 (open)
<warn> [1561707240.199031] checking if connected failed: Couldn't check current list of active PDP contexts: Serial command timed out
<debug> [1561707240.199127] (ttyUSB3) device open count is 4 (close)
<warn> [1561707240.199244] (tty/ttyUSB3) at port timed out 9 consecutive times
<debug> [1561707240.199363] (ttyUSB3): --> 'AT+CNSMOD?<CR>'
<debug> [1561707243.198163] Couldn't refresh access technologies: 'Serial command timed out'
<debug> [1561707243.198294] Periodic signal quality checks scheduled in 30s
<debug> [1561707243.198402] (ttyUSB3) device open count is 3 (close)
<error> [1561707243.198528] (tty/ttyUSB3) at port timed out 10 consecutive times, marking modem '/org/freedesktop/ModemManager1/Modem/0' as invalid
<debug> [1561707243.198699] (ttyUSB3): --> 'AT+CGACT?<CR>'
<debug> [1561707243.199846] Removing from DBus bearer at '/org/freedesktop/ModemManager1/Bearer/0'
<debug> [1561707243.200103] [device /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3] unexported modem from path '/org/freedesktop/ModemManager1/Modem/0'
<debug> [1561707243.200214] Periodic signal checks disabled
<debug> [1561707243.200867] Extended signal information reporting disabled
<warn> [1561707243.214930] checking if connected failed: Couldn't check current list of active PDP contexts: AT command was cancelled
<debug> [1561707243.215132] (ttyUSB3) device open count is 2 (close)
<debug> [1561707243.215278] (ttyUSB3): --> 'AT+CGACT?<CR>'
<warn> [1561707243.226978] checking if connected failed: Couldn't check current list of active PDP contexts: AT command was cancelled
<debug> [1561707243.227192] (ttyUSB2): port now disconnected
<debug> [1561707243.227391] (ttyUSB3) device open count is 1 (close)
<debug> [1561707243.227484] (ttyUSB2) device open count is 1 (close)
<debug> [1561707243.227651] (ttyUSB2) forced to close port
<debug> [1561707243.227712] (ttyUSB2) device open count is 0 (close)
<debug> [1561707243.228003] (ttyUSB2) closing serial port...
<debug> [1561707243.228146] (ttyUSB2) serial port closed
<debug> [1561707243.228307] (ttyUSB3) device open count is 0 (close)
<debug> [1561707243.228393] (ttyUSB3) closing serial port...
<debug> [1561707243.229458] (ttyUSB3) serial port closed
<debug> [1561707243.229547] (ttyUSB0) device open count is 0 (close)
<debug> [1561707243.229610] (ttyUSB0) closing serial port...
<debug> [1561707243.230264] (ttyUSB0) serial port closed
<debug> [1561707243.230378] (ttyUSB0) forced to close port
<debug> [1561707243.230496] Modem (SimTech) '/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3' completely disposed
<debug> [1561707243.230790] (ttyUSB3) forced to close port