Re: [git patches] libata updates for 2.6.37

[Tejun Heo]

Hello, again.

On 12/01/2010 01:44 PM, Kyle McMartin wrote:
> 00:1f.2 SATA controller [0106]: Intel Corporation 5 Series/3400 Series
...
> 	Model Number:       HITACHI HTS725032A9A364                 

Nothing peculiar.  Hmm... okay, I think I've found what went wrong.
Can you please try the following patch and see whether the problem
goes away?

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 5e59050..17a6378 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -3275,6 +3275,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 	struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
 	struct ata_eh_context *ehc = &link->eh_context;
 	struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
+	enum ata_lpm_policy old_policy = link->lpm_policy;
 	unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
 	unsigned int err_mask;
 	int rc;
@@ -3338,6 +3339,14 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 		goto fail;
 	}

+	/*
+	 * Low level driver acked the transition.  Issue DIPM command
+	 * with the new policy set.
+	 */
+	link->lpm_policy = policy;
+	if (ap && ap->slave_link)
+		ap->slave_link->lpm_policy = policy;
+
 	/* host config updated, enable DIPM if transitioning to MIN_POWER */
 	ata_for_each_dev(dev, link, ENABLED) {
 		if (policy == ATA_LPM_MIN_POWER && ata_id_has_dipm(dev->id)) {
@@ -3353,12 +3362,14 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 		}
 	}

-	link->lpm_policy = policy;
-	if (ap && ap->slave_link)
-		ap->slave_link->lpm_policy = policy;
 	return 0;

 fail:
+	/* restore the old policy */
+	link->lpm_policy = old_policy;
+	if (ap && ap->slave_link)
+		ap->slave_link->lpm_policy = old_policy;
+
 	/* if no device or only one more chance is left, disable LPM */
 	if (!dev || ehc->tries[dev->devno] <= 2) {
 		ata_link_printk(link, KERN_WARNING,
--
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