Date: Sat, 13 Jul 1996 17:03:24 +0200 (MET DST) From: Thomas Graichen <graichen@axp5.physik.fu-berlin.de> To: bde@zeta.org.au (Bruce Evans) Cc: hackers@FreeBSD.org Subject: Re: sio / modem problems Message-ID: <199607131503.RAA01130@mordillo> In-Reply-To: <199607112254.IAA18667@godzilla.zeta.org.au> from "Bruce Evans" at Jul 12, 96 08:54:57 am
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hasn't Bruce Evans said ? ...
>
> >> i have an internal creatix phone-master modem - which will be detected in
> >> FreeBSD 2.0.5 but not in the 2.1.0 RELEASE or the march 2.2 snap - it's
>
> The probe didn't change (not even one byte of the source) between 2.0.5R
> and 2.1.0R.
>
> Revision 1.135 on 25 Feb introduced some delays in the probe in the hope
> of fixing this problem. These should be in the March 2.2 snap.
>
> These changes are missing from -stable :-(. (Or `:-)' if they actually
> make things worse :-).
>
> The probe hasn't changed significantly in -current since rev.1.135.
>
> >I recently fixed a modem detection problem from someone by inserting
> >"DELAY(1000);"'s in sioprobe() everywhere the /* EXTRA DELAY? */ comment
> >appeared. It's a hack, but clearly some portion of that code is running
>
> The delays in rev.1.135 are in slightly different places. They are
> probably necessary if the UART is actually a bunch of i/o ports under
> software control. The software can reasonably take a long time to
> complete a sequence of events that it initiates. OTOH, for events
> initiated by the host cpu, such as writes to control registers, the
> UART needs to respond withing a few hundred nsec to preserve 16550
> compatibility. Otherwise back to back writes to a control register
> might lose the intermediate steps... I added delays in exactly the
> cases where it seems reasonable for the UART to be slow.
>
but they are not enough :-) - but i solved it (half) - i disabled the "fast AT
cycle option" and now it is detected fine - i found that out after playing
around a bit with the 2.0.5 kernel (the generic detected it but a smaller
kernel built for my system not - 2.0.5 too - this way i found out that it is
some kind of timing problem - it is detected by all kernels if i turned off
the turbo switch of the computer - this way i came to the bios setting)
now the question is - can it be solved by software (some more delays)
because linux detects it fine ?
t
p.s.: thanks to all the people who replied to my question
--
thomas graichen graichen@mail.physik.fu-berlin.de graichen@FreeBSD.org
perfection is reached, not when there is no longer anything to add, but when
there is no longer anything to take away antoine de saint-exupery
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