Use it to reset controller and to select data rate. According to Intel
80277AA datasheet, software reset behaves the same as DOR reset except
that it is self clearing. National Semiconductor PC8477B datasheet says
the same. As a side effect, we no longer use Configuration Control
Register (CCR) at 0x3f7 for these controllers, which is often missing
in modern hardware.
number of dma overruns/underruns for systems under heavy dma load.
As a side effect, broken enhanced floppy controllers that sometimes
don't detect dma overruns/underruns will give less errors.
Reviewed by: j@uriah.heep.sax.de (J Wunsch)
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
floppy driver (or in the hardware?). It turned out to be caused by
spurious interrupts, right after an FDC reset.
Also major cleanup in the low-level structure, there are now functions
performing error-checks for the FDC I/O.
Submitted by: (mostly) Peter Dufault <dufault@FreeBSD.org>
date: 1994/05/22 12:35:38; author: joerg; state: Exp; lines: +6 -6
First round of floppy changes. Try making `fd' more robust.
New features:
. ioctl command for setting the drive type (density etc.); restricted
to the super-user
. ioctl for getting/seting `drive options'; currently only option
is FDOPT_NORETRY: inhibit the usual retries; used when verifying
a newly formatted track
Fixes:
. function prototypes
. made all internal functions `static'
. cleaned up & corrected .h files
. restructured, to make the chaotic function sequence more rational
. compiled with -Wall, and cleared all warnings
. introduced a mirror for the (write-only) `digital output register',
to avoid the current kludge
. device probing completed by seeking/recalibrating, and looking
for track 0 being found
. holding the controller down in reset state while it is idle (and
thus saving allot of headaches)
. make requests fail that are not a multiple of the (physical)
sector size
. removed the fixed physical sector size (512 bytes), allowing for any
size the controller could handle (128/256/512/1024 bytes)
. replaced some silly messages
. fixed the TRACE* macro usage, debugging reports should be complete
now again (debugging output is HUGE! though)
. removed fd_timeout for SEEK command; seeks are always reported by
the controller to succeed, since the `success' only refers to the
controller's idea of success - there is no hardware line to tell about
the seek end (other than the `track 0' line)
. catch SENSEI's that report about a `terminated due to READY changed'
status - could happen after a controller reset
. converted ``hz / <something>'' divide operations to divisors that are
powers of two, so gcc can optimize them into shifts
. write/format operations are checked against a write-protected medium
now *prior* starting the operation
. error reports of `invalid command' and `wrong cylinder' will cause
shortcuts in the retrier() now
. fixed a bug in the retrier() causing bogus block numbers to be reported
. fdformat() does care for errors now
Known Bugs:
. no attempts have been made (yet) to improve the performance
. sometimes, bogus ``seek/recalib failed'' messages are logged; this
is still a bug in the driver, but it's not harmful since it's
usually caught by the retrier()
Reviewed by:
Submitted by:
Obtained from:
