From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/ata/libata-core.c | 48 +++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 4 deletions(-)
diff -puN drivers/ata/libata-core.c~libata-isolate-and-rework-cable-logic drivers/ata/libata-core.c
--- a/drivers/ata/libata-core.c~libata-isolate-and-rework-cable-logic
+++ a/drivers/ata/libata-core.c
@@ -4536,6 +4536,49 @@ static int ata_is_40wire(struct ata_devi
}
/**
+ * 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
*
@@ -4603,10 +4646,7 @@ static void ata_dev_xfermask(struct ata_
*/
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);
_
--
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