Messages in this thread | | | From | Lars Poeschel <> | Subject | Re: [RFC DO NOT MERGE] tty: n_gsm: support buggy modem | Date | Wed, 08 Jan 2014 14:26:03 +0100 |
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Am Dienstag, 7. Januar 2014, 16:51:37 schrieb Alan Cox: > > > modem status command, but this DV bit is not set. With this patch the > > > modem > > > and the whole mux is working fine. Another way makeing all this work is > > > setting the carrier_raised function to NULL. The tty code assumes that > > > everything is alright then. > > Which means your modem has decided it doesn't yet have a carrier. Do you > get a carrier after ATD completes with a CONNECTED message ? > > (you can open with O_NDELAY to avoid blocking on the open)
Oh! Thank you! This does indeed bring up the channel. After opening nonblocking and writing ATD *99***1# to a muxed channel the modem sends a modem status command message with DV bit set. This does in fact mean, I can only use the mux in nonblocking mode. Does this make sense ? Why can't I use a muxed channel with blocking IO ? I could do AT commands over the mux channel and the DV bit is not set (and thus TIOCM_CD is not set) and the modem (and the mux line discipline) is fine with it.
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