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Date:      Thu, 30 Nov 1995 11:58:19 +0000 ()
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        awebster@dataradio.com (Andrew Webster)
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: Strange Multi-port SIO behaviour
Message-ID:  <199511301158.LAA13448@genesis.atrad.adelaide.edu.au>
In-Reply-To: <199511291539.KAA05360@vhf.dataradio.com> from "Andrew Webster" at Nov 29, 95 10:40:27 am

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Andrew Webster stands accused of saying:
> 
> I've noticed on systems with AST/4 port and Digi PC/4/8 cards that 
> when a soft-reboot occurs (i.e. after crash/panic), the SIO ports are 
> not all initialized properly, whereas after a shutdown -r or reboot, 
> or cold boot the ports all init properly.  

Can you please note the state of the ports when their probes fail? 
In particular, DCD and rx status info are vital.  Also, enable verbose
probing (flags & 0x80) on all the ports, and let us know which tests
fail.

> I've looked at the sioprobe function in the sio.c module and there 
> appears to be lots of instances where the programmer added 
> EXTRA_DELAY?  Has anyone else seen this problem?

The EXTRA DELAY comments appear to be mostly pertinent to emulated serial 
ports on cheapo internal modems, but NOBODY HAS GOTTEN BACK TO ME ON THIS 
ONE 8( **GRR**

> Appart from forcing the machine to reboot if all the sio ports are 
> not detected, is there a clean way to make sioprobe find all the 
> ports after a crash?

At the moment, the problem _seems_ to be due to UARTs that are already
initialised either receiving or still sending data, or possibly having 
DCD state change interrupts pending.

It's probably worth adding code to the probe to try to hang modems up, and 
so forth, but it's not easy to guarantee a successful probe if the device
is receiving data.

It may simply be easier to add another flag bit that says "assume the port
is there, regardless of the probe results"

Comments, Bruce?

>   Andrew Webster   Network Manager / Special Projects

-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
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