Commit 15a5551c authored by Alan Cox's avatar Alan Cox Committed by Jeff Garzik
Browse files

libata: isolate and rework cable logic 



Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent d21279f4

drivers/ata/libata-core.c

+44 −4
Original line number Diff line number Diff line
@@ -3885,6 +3885,49 @@ static int ata_is_40wire(struct ata_device *dev) 
	return ata_drive_40wire(dev->id);

}



/**

 *	cable_is_40wire		-	40/80/SATA decider

 *	@ap: port to consider

 *

 *	This function encapsulates the policy for speed management

 *	in one place. At the moment we don't cache the result but

 *	there is a good case for setting ap->cbl to the result when

 *	we are called with unknown cables (and figuring out if it

 *	impacts hotplug at all).

 *

 *	Return 1 if the cable appears to be 40 wire.

 */



static int cable_is_40wire(struct ata_port *ap)

{

	struct ata_link *link;

	struct ata_device *dev;



	/* If the controller thinks we are 40 wire, we are */

	if (ap->cbl == ATA_CBL_PATA40)

		return 1;

	/* If the controller thinks we are 80 wire, we are */

	if (ap->cbl == ATA_CBL_PATA80 || ap->cbl == ATA_CBL_SATA)

		return 0;

	/* If the controller doesn't know we scan



	   - Note: We look for all 40 wire detects at this point.

	     Any 80 wire detect is taken to be 80 wire cable

	     because

	     - In many setups only the one drive (slave if present)

               will give a valid detect

             - If you have a non detect capable drive you don't

               want it to colour the choice

        */

	ata_port_for_each_link(link, ap) {

		ata_link_for_each_dev(dev, link) {

			if (!ata_is_40wire(dev))

				return 0;

		}

	}

	return 1;

}



/**

 *	ata_dev_xfermask - Compute supported xfermask of the given device

 *	@dev: Device to compute xfermask for
@@ -3953,10 +3996,7 @@ static void ata_dev_xfermask(struct ata_device *dev) 
	 */

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

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

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

		    (ata_is_40wire(dev) &&

		    (ap->cbl == ATA_CBL_PATA_UNK ||

		     ap->cbl == ATA_CBL_PATA80))) {

		if (cable_is_40wire(ap)) {

			ata_dev_printk(dev, KERN_WARNING,

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

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