Date: Tue, 28 Nov 1995 23:49:24 +1100 (EST) From: David Dawes <dawes@rf900.physics.usyd.edu.au> To: bde@zeta.org.au (Bruce Evans) Cc: hackers@FreeBSD.ORG Subject: Re: Problem with sio probe and Mach64 PCI video card Message-ID: <199511281249.XAA17851@rf900.physics.usyd.edu.au> In-Reply-To: <199511281231.XAA28803@godzilla.zeta.org.au> from "Bruce Evans" at Nov 28, 95 11:31:18 pm
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>>I've just installed an ASUS PCI-AV264CT video card, based on the
>>Mach64 "CT" chipset, into an ASUS PCI/I-P54TP4 motherboard with 90MHz
>>Pentium CPU. I'm planning to do some work on getting Mach64 CT support
>>into XFree86. When I booted FreeBSD 2.1, the screen went blank fairly
>>early in the boot probe sequence. When connected to a DPMS monitor,
>>it went into "OFF" mode indicating no sync present. After a bit of
>>experimentation I found that this problem could be avoided by disabling
>>the two sio devices I had configures (sio0 and sio1). Enabling either
>>one separately still resulted in the problem.
>
>>I've previously seen the video go blank for a fraction of a second when
>>booting on a similar machine with an S3 964 card installed. I wondered
>>why this happened, but since it didn't cause any problems I thought nothing
>>more of it.
>
>>My guess is that the sio probe is writing to a Mach64 register. In the
>>S3 case it is possilbly successfully restoring it too. I haven't had
>
>sio always writes 0 to port 0x2E8+4 (the modem control reg for the usual
>sio3 address) if >= 1 sio device is configured. It doesn't attempt to
>restore the original value; however, if sio3 is enabled at port IO_COM4,
>as it is in GENERIC, then other values will be written to 0x2EC and nearby.
>
>The change at the end replaces bogus internal array of ports by the ones
>specified in the config. This requires the config to specify sio2 and
>sio3 if the ports exist even if they are unusable under FreeBSD due to
>a conflict, and S3 owners to boot with -c and disable sio3 before the
>monitor blows up :-). sio3 shouldn't be in GENERIC.
The patch fixes the problem -- thanks! I don't understand why this means
that the config must specify ports that are not usable under FreeBSD.
I think "S3 owners" should be replaced by "IBM8514/A, S3, Mach{8,32,64}
and any chipset with an 8514/A ancestory owners".
David
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