Date: Fri, 23 Nov 2001 13:33:45 +0100 From: Gary Jennejohn <garyj@jennejohn.org> To: Leif Neland <leifn@neland.dk>, <freebsd-isdn@freebsd.org> Subject: Re: bidirectional /dev/i4btel0 ? Message-ID: <200111231519.fANFJep38061@peedub.muc.de> In-Reply-To: <20011123124125.V38153-100000@arnold.neland.dk> References: <20011123124125.V38153-100000@arnold.neland.dk>
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On Friday 23 November 2001 13:04, Leif Neland wrote:
> Is it somehow possible to both be sending and recieving from
> /dev/i4btel0?
>
> I would like to send voice to the caller, while also recieving
> data, eventually decoding with dtmfdecode to make a
> voice-response system.
>
> dd of=${DEVICE} if=${LIBDIR}/leifans.al bs=2k >/tmp/out.log
> 2>&1 & sleep 2
> dd if=${DEVICE} of=/tmp/answers.al bs=2k count=100
> >/tmp/in.log 2>&1
>
>
> Without "sleep" the last dd reports "device busy"
> With "sleep" the first dd reports "device busy"
>
Reception is taking longer than 2 seconds, so the first dd fails
because of that.
> Would it be possible for a single program to open the device
> for reading and writing simultaneously?
>
Right now the tel device is exclusive open, so only one process
at a time can have it open. However, I don't see anything which
would indicate that opening it RW would fail.
However, the way that i4btelread and i4btelwrite are implemented
it doesn't look like simultaneous reads and writes are possible.
The kernel puts the process to sleep while waiting either to
receive or send the data, so the process can only be doing one
of the two at any given time.
Without rewriting the i4btel driver there's no way to do what
you want, AFAICT.
--
Gary Jennejohn garyj@jennejohn.org gj@freebsd.org
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