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    SubjectRe: FDC motor left on
    On Sat, 4 Oct 2003, Dave Jones wrote:

    > On Fri, Oct 03, 2003 at 01:25:30PM -0400, Richard B. Johnson wrote:
    > > In linux-2.4.22 and earlier, if there is no FDC driver installed,
    > > the FDC motor may continue to run after boot if the motor was
    > > started as part of the BIOS boot sequence.
    > > This patch turns OFF the motor once Linux gets control.
    > >
    > >
    > > --- linux-2.4.22/arch/i386/boot/setup.S.orig Fri Aug 2 20:39:42 2002
    > > +++ linux-2.4.22/arch/i386/boot/setup.S Fri Oct 3 11:50:43 2003
    > > @@ -59,6 +59,8 @@
    > Does this mean the 'kill_motor' function in bootsect.S isn't doing
    > what it should be? If so, maybe that needs fixing instead of turning
    > it off in two places ?
    > Dave

    Yes. I didn't even see that. The code there makes me kinda sick.
    Anyway, the kill_motor function executes "reset diskette/disk" function
    which will never turn OFF the drive. Instead, it will restart
    the motor timer because, as a condition of reseting the diskette,
    it must make sure the motor is running.

    I suggest that the FDC control byte be read, then the result be
    ANDed with ~0x10, then written back. The ifed-out code clears
    the whole control word which is inappropriate at a time the
    diskette channel may be still be active.

    Dick Johnson
    Penguin : Linux version 2.4.22 on an i686 machine (797.90 BogoMips).
    Note 96.31% of all statistics are fiction.

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