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From: Bruce Evans <bde@FreeBSD.ORG>
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	Wed, 29 Jul 1998 06:00:44 -0700 (PDT)
Date: Wed, 29 Jul 1998 06:00:44 -0700 (PDT)
Message-Id: <199807291300.GAA10797@freefall.freebsd.org>
To: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject: cvs commit: src/sys/i386/isa fd.c fdc.h
Sender: owner-cvs-all@FreeBSD.ORG
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bde         1998/07/29 06:00:44 PDT

  Modified files:
    sys/i386/isa         fd.c fdc.h 
  Log:
  Fixed error handling:
  - Call isa_dmadone() whenever necessary to stop DMA and/or free bounce
    buffers.  Undead DMA corrupted the malloc freelist fairly consistently
    in the following configuration: SLICE kernel, 2 floppy drives, no disk
    in fd0, disk in fd1.
  - Don't call fdc_reset() from fd_timeout().  Doing so gave an "extra"
    interrupt which was usually misinterpreted as being for completion
    of the next FDC command; the interrupt for completion of the next
    FDC command was then usually misinterpreted...  There were further
    complications for interrupts latched by the soft-spl mechanism so
    that they were delivered after all the h/w interrupts went away.
    This caused at least wrong head settle delays and may be why the
    FreeBSD floppy driver seems to munch floppies more than most floppy
    drivers.  The reset was unnecessary anyway in cases that didn't have
    the bug described next, since is was repeated a little later for
    the IOTIMEDOUT state.  The state machine has complications to handle
    resets correctly, so just use it.
  - Don't call retrier() from fd_timeout().  The IOTIMEDOUT state needs
    to be processed next, and it isn't valid to set to that state if
    retrier() has aborted the current transfer.  Doing so caused null
    pointer panics after the previous bug was fixed.
  
  Improved error handling:
  - If an i/o is aborted, arrange to reset in the state machine before
    doing the next i/o.  New fdc flag for this.  This fixes spurious
    warnings and lengthy busy-waiting for the next i/o.
  - Split STARTRECAL into RESETCOMPLETE and STARTRECAL and only check
    for the results from reset if we actually reset.  This fixes spurious
    warnings for other paths to STARTRECAL.  [Oops, it may break reset
    handling for motor-off resets.]
  
  Cleanups in fd_timeout():
  - Renamed to fd_iotimeout() to make it clearer that it is only used
    for i/o.
  - Don't handle the bp == 0 case.  This case can't happen for i/o.
  - Don't check for controller-busy.  We know it must be.
  - Don't print anything.  retrier() already prints too much for normal
    errors.
  - Fudge the state differently so that the state machine advances
    fdc->retry and the status is invalid (perhaps this should fudge a
    valid state like the one for WP).
  - Style fixes.
  
  Revision  Changes    Path
  1.120     +61 -56    src/sys/i386/isa/fd.c
  1.11      +2 -1      src/sys/i386/isa/fdc.h