Date: Sat, 13 Jan 1996 18:38:35 +0100 (MET) From: Geert Bosch <geert@sun3.iaf.nl> To: bugs@freebsd.org Subject: Re: ATI Mach-64 problems in Textmode!!! Message-ID: <Pine.SUN.3.91.960113182741.22669A-100000@fozzie.sun3.iaf.nl>
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Dear developers,
There is a bug in FreeBSD which leads to unexpected conflicts between
serial ports and the ATI Mach-64 Xpression PCI-based video card: the
FreeBSD kernel writes to the IO-port at address 0x2ec when it shouldn't,
resulting in a black screen during kernel load.
I experienced the bug using FreeBSD-v2.05, but I got mail from other
users who had the same problem with FreeBSD-v2.1. There is a workaround
for this bug, but it's not trivial and should be included in the FAQ.
The IO-port at 0x2ec is used by both the sio driver and the ATI Mach.
Disabling the fourth sio-port (at 0x2e8) should prevent sio from accessing the
port, but unfortunately it does not. The work-around is to disable *all*
serial ports and then build a custom kernel with a patch in sio.c to remove
the address of the fourth serial port. Note that not all ATI Mach-64
cards exhibit this problem, as it seems it only surfaces with the
ATI Mach-64 Xpression.
Could you please add this to the FAQ and/or change the drivers so
other people won't have as much trouble in getting even the boot-floppy
to load as I had.
Thanks for your hard work!
Greetings,
Geert
PS. Could you in any case send a confirmation of my bug-report?
E-Mail: geert@sun3.iaf.nl
Phone: +31-53-4303054
---------- Forwarded message ----------
Date: Sat, 13 Jan 96 14:32:30 GMT
From: John Lucas <jlucas@uvi.edu>
To: geert@fozzie.sun3.iaf.nl
Subject: Re: ATI Mach-64 problems in Textmode!!!
>I have a very strange problem with FreeBSD v2.05R (didn't receive the
>new one yet) and my ATI Mach-64 Xpression PCI videocard with 1 MB DRAM.
>The kernel loads fine, but after that I get (when it starts
>initializing hardware) a strange video-effect occurs and my screen
>turns black and it looks like the (black) picture isn't synchronized
>anymore. I tried to disable all devices which were not needed,
>(including the possibly conflicting 4th serial port at 0x2E8) but that
>didn'd help. Replacing the ATI Mach-64 with an old ET4000 fixed the
>problem. Note that I'm not talking about X-Windows, but just the
>normal text-mode.
>
You will have to disable ALL of your sio ports to get around this problem. Once
installed you can generate a new kernal w/o code for sio3 AND you will need to
change the file /usr/src/sys/i386/isa/sio.c. Change:
static Port_t likely_com_ports[] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8, };
to
static Port_t likely_com_ports[] = { 0x3f8, 0x2f8, 0x3e8, };
If this isn't in the FAQ it should be. I am running v2.1-SNAPxxxx and I had the
same problem with the same hardware (ATI Xpression) and it works fine now
(actually I dropped sio2 and sio3, since I only have 2 com ports).
| John Lucas jlucas@uvi.edu |
| Academic Computing NIC Handle: JL423 |
| University of the Virgin Islands (809) 693-1216 |
| St. Thomas, VI 00802 http://www.uvi.edu/jlucas.html |
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