Subject: Re: More on our AC'97 modem support in auich(4)
To: Jared D. McNeill <email@example.com>
From: Matthias Drochner <M.Drochner@fz-juelich.de>
Date: 04/26/2005 11:25:08
> It would be great if we got slmodem-2.9.9b up and running on NetBSD to
> the point where we can do PPP over it!
Now that you fixed one if the problems which made slmodemd fail...
(One needed to do the SETFD ioctl _before_ the SETINFO, otherwise
the audio driver wasn't set to full-duplex correctly.)
I still didn't even manage to dial a phone number through the soft
modem up to now (but I couldn't invest much time yet). There
are still some quite serious problems:
-The frequencies (analyzed DTMF tones coming out at the other end)
are off by about 20%. If I set the sample rate to 9600, it looks
pretty correct. The driver needs a modification to allow this.
-I'm not sure whether some in-kernel rate conversion gets in between.
We should make sure that doesn't happen, it probably doesn't do
any good. The code is rather confusing, and it is probably not worth
investing time here because the audio middle layer is being reworked
-The gain/mixer stuff has problems: The mapping of 4-bit
hardware values to the user visible 0..255 range loses a bit
somewhere, and settings get lost on SETINFO calls unexpectedly.
> So, beer for whoever mails me a patch first for slmodem-2.9.9b using a
> dial-up account, connected through auich(4) and PPP on NetBSD. You have
> to come to Saint John to pick it up though ;)
While I like both beer and the Fundy area a lot, my day job doesn't
leave me as much time as needed for that atm, unfortunately.