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Commit 8343f889 authored by Robert Hancock's avatar Robert Hancock Committed by Jeff Garzik
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libata: warn if speed limited due to 40-wire cable 



Warn the user if a drive's transfer rate is limited because of a 40-wire
cable detection.

Signed-off-by: default avatarRobert Hancock <hancockr@shaw.ca>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent f0ef88ed

drivers/ata/libata-core.c

+20 −13
Original line number Diff line number Diff line
@@ -3425,19 +3425,7 @@ static void ata_dev_xfermask(struct ata_device *dev) 
	xfer_mask = ata_pack_xfermask(ap->pio_mask,

				      ap->mwdma_mask, ap->udma_mask);



	/* Apply cable rule here.  Don't apply it early because when

	 * we handle hot plug the cable type can itself change.

	 */

	if (ap->cbl == ATA_CBL_PATA40)

		xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);

	/* Apply drive side cable rule. Unknown or 80 pin cables reported

	 * host side are checked drive side as well. Cases where we know a

	 * 40wire cable is used safely for 80 are not checked here.

	 */

        if (ata_drive_40wire(dev->id) && (ap->cbl == ATA_CBL_PATA_UNK || ap->cbl == ATA_CBL_PATA80))

		xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);





	/* drive modes available */

	xfer_mask &= ata_pack_xfermask(dev->pio_mask,

				       dev->mwdma_mask, dev->udma_mask);

	xfer_mask &= ata_id_xfermask(dev->id);
@@ -3469,6 +3457,25 @@ static void ata_dev_xfermask(struct ata_device *dev) 
	if (ap->ops->mode_filter)

		xfer_mask = ap->ops->mode_filter(ap, dev, xfer_mask);



	/* Apply cable rule here.  Don't apply it early because when

	 * we handle hot plug the cable type can itself change.

	 * Check this last so that we know if the transfer rate was

	 * solely limited by the cable.

	 * Unknown or 80 wire cables reported host side are checked

	 * drive side as well. Cases where we know a 40wire cable

	 * is used safely for 80 are not checked here.

	 */

	if (xfer_mask & (0xF8 << ATA_SHIFT_UDMA))

		/* UDMA/44 or higher would be available */

		if((ap->cbl == ATA_CBL_PATA40) ||

   		    (ata_drive_40wire(dev->id) &&

		     (ap->cbl == ATA_CBL_PATA_UNK ||

                     ap->cbl == ATA_CBL_PATA80))) {

		      	ata_dev_printk(dev, KERN_WARNING,

				 "limited to UDMA/33 due to 40-wire cable\n");

			xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);

		}



	ata_unpack_xfermask(xfer_mask, &dev->pio_mask,

			    &dev->mwdma_mask, &dev->udma_mask);

}