Re: [PATCH 07/11] the latest consensus libata resume fix

From: Marcel Holtmann
Date: Sat Jun 03 2006 - 04:51:10 EST


Hi Jens,

> > -stable review patch. If anyone has any objections, please let us know.
> > ------------------
> >
> > From: Mark Lord <liml@xxxxxx>
> >
> > Okay, just to sum things up.
> >
> > This forces libata to wait for up to 2 seconds for BUSY|DRQ to clear
> > on resume before continuing.
> >
> > [jgarzik adds...] During testing we never saw DRQ asserted, but
> > nonetheless (a) this works and (b) testing for DRQ won't hurt.
> >
> > Signed-off-by: Mark Lord <liml@xxxxxx>
> > Acked-by: Jens Axboe <axboe@xxxxxxx>
> > Signed-off-by: Jeff Garzik <jeff@xxxxxxxxxx>
> > Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
> > ---
> >
> > drivers/scsi/libata-core.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > --- linux-2.6.16.19.orig/drivers/scsi/libata-core.c
> > +++ linux-2.6.16.19/drivers/scsi/libata-core.c
> > @@ -4293,6 +4293,7 @@ static int ata_start_drive(struct ata_po
> > int ata_device_resume(struct ata_port *ap, struct ata_device *dev)
> > {
> > if (ap->flags & ATA_FLAG_SUSPENDED) {
> > + ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 200000);
> > ap->flags &= ~ATA_FLAG_SUSPENDED;
> > ata_set_mode(ap);
> > }
>
> I'm not against the patch as such, but last I checked 2.6.16 actually
> worked ok. The timer fixes in 2.6.17-rc is what apparently got the
> resume breaking.
>
> So unless there's a bug report on 2.6.16.x for this, then it's a little
> against the -stable rules to add it.

I had problems with resume on my IBM X41 since I got it (something
around 2.6.15) and only this patch made it work again.

Because of the SDHCI stuff I always used the latest kernel and thus I
wasn't sure if there actually was a problem or not. So I tested a plain
2.6.16 with and without this patch. The plain 2.6.16 doesn't resume on
my IBM X41 laptop. If I apply this patch, the resume works perfect.

Regards

Marcel


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