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: Robert Hancock <hancockr@shaw.ca>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 99a8815..93e7b99 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3425,19 +3425,7 @@
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 @@
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);
}