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SubjectRe: [PATCH] Fix floppy hibernation
On Tue, 2 Jun 2009 18:30:50 +0200
Ondrej Zary <linux@rainbow-software.org> wrote:

> > > +static int floppy_resume(struct platform_device *dev)
> > > +{
> > > + int i;
> > > +
> > > + for (i = 0; i < N_FDC; i++)
> > > + if (FDCS->address != -1)
> > > + user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > > +
> > > + return 0;
> > > +}
> >
> > hm, how does this work?
> >
> > FDCS is a revolting should-not-exist macro which assumes the presence
> > of a local variable called `fdc'.
>
> The driver is complete mess - there is also a global static fdc variable.
> So it worked because I have only one floppy controller.
>
> > So I think the loop control variable here should be called `fdc', not `i'.
>
> See the v2 patch below. Tested and works too.

OK.

> >
> > It's pretty amazing that something like this still exists in a core
> > driver. Someone please save us!
>
>
>
>
> Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> resume from hibernation, at least on my machine.
>

That's a very skimpy changelog. The lack of any useful reference to
the referred-to Ingopatch doesn't aid things..

> --- linux-2.6.29.4-orig/drivers/block/floppy.c 2009-05-30 14:38:29.000000000 +0200
> +++ linux/drivers/block/floppy.c 2009-06-02 17:32:56.000000000 +0200
> @@ -4148,6 +4148,24 @@
> {
> }
>
> +static int floppy_resume(struct platform_device *dev)
> +{
> + int fdc;
> +
> + for (fdc = 0; fdc < N_FDC; fdc++)
> + if (FDCS->address != -1)
> + user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> +
> + return 0;
> +}

The patch changes the driver so that it calls user_reset_fdc() for each
device at resume-time.

Why? What effect does this have on the hardware and why does it fix things?

Thanks.



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