Subject: Re: Hanging problems
To: None <current-users@NetBSD.ORG>
From: Brad Spencer <email@example.com>
Date: 05/11/1995 09:10:04
>This seemed to indicate that the problem was to do with probing for floppy
>drives after the first, so I changed the "for" loop in fd.c to only check for
>one drive. The resulting kernel booted fine (with the external cache enabled).
>A slightly better fix seemed to be to change the config file to explicity name
>the fd device, rather than use wildcards. Ie:
> fd0 at fdc0 drive 0
>Again this kernel booted fine. As an experiment, I added explicitly configured
>additional floppy drives one at a time, and found the machine hung when booting
>a kernel with four floppy drives configured. It also hung with less than 4
>drives when I didn't explicitly provide drive numbers. Ie:
> fd0 at fdc0 drive ?
> fd1 at fdc0 drive ?
>I guess this indicates some kind of hardware bug, but I would appreciate any
>comments on: 1) why turning the external cache off changes the behaviour; 2)
>what the floppy probe code could be doing to cause this, and whether there is a
>nicer fix than explicitly naming the fd devices.
>Thanks in advance.
I belive I have seen this probe-for-non-present-floppy-and-crash
behavior on my P90 with a VLB multi-I/O card. For me anyway, when the
probe hits the NE7CMD_SENSEI command, everything goes all funny. The
video mode is messed with and junk is written to the screen. Puting a
'return 1' in before the SENSEI command seems to allow the boot to
/* select drive and turn on motor */
outb(iobase + fdout, drive | FDO_FRST | FDO_MOEN(drive));
/* wait for motor to spin up */
/* wait for recalibrate */
n = fdcresult(fdc);
I figured that this behavior was caused by a buggy multi-I/O card and
since I don't really use floppy disks very often, it wasn't a big
priority for me.
Brad Spencer - firstname.lastname@example.org [work]
email@example.com [more work]