[PATCH 6/6] ata_piix: don't scan non-existent device

[Tejun Heo <htejun@gmail.com>]

ata_std_softreset() sometimes reports presence of dev 1 even when it
doesn't exist (PCS-wise).  This usually happens reading dev 1's
signature returns that of dev 0 (e.g. on ICH6M).  This patch turns off
non-existent device on such cases.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/ata_piix.c |   25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

cda8686b4ad82a9272748af4388d47475c6acb2b
diff --git a/drivers/scsi/ata_piix.c b/drivers/scsi/ata_piix.c
index 72e38e6..625db11 100644
--- a/drivers/scsi/ata_piix.c
+++ b/drivers/scsi/ata_piix.c
@@ -566,14 +566,31 @@ static unsigned int piix_sata_probe (str
  */
 static int piix_sata_probe_reset(struct ata_port *ap, unsigned int *classes)
 {
-	if (!piix_sata_probe(ap)) {
+	unsigned int mask;
+	int i, rc;
+
+	mask = piix_sata_probe(ap);
+	if (!mask) {
 		printk(KERN_INFO "ata%u: SATA port has no device.\n", ap->id);
 		return 0;
 	}
 
-	return ata_drive_probe_reset(ap, ata_std_probeinit,
-				     ata_std_softreset, NULL,
-				     ata_std_postreset, classes);
+	rc = ata_drive_probe_reset(ap, ata_std_probeinit,
+				   ata_std_softreset, NULL,
+				   ata_std_postreset, classes);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < 2; i++) {
+		if (ata_class_present(classes[i]) && !(mask & (1 << i))) {
+			printk(KERN_WARNING "ata%u: dev %u class %d for "
+			       "non-existent device, fixing up\n",
+			       ap->id, i, classes[i]);
+			classes[i] = ATA_DEV_NONE;
+		}
+	}
+
+	return 0;
 }
 
 /**
-- 
1.2.1