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Commit e5005b15 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

libata: issue DIPM enable commands with LPM state updated 



Low level drivers may behave differently depending on the current
link->lpm_policy.  During ata_eh_set_lpm(), DIPM enable commands are
issued after the successful completion of ap->ops->set_lpm(), which
means that the controller is already in the target state.  This causes
DIPM enable commands to be processed with mismatching controller power
state and link->lpm_policy value.

In ahci, link->lpm_policy is used to ignore certain PHY events if LPM
is enabled; however, as DIPM commands are issued with stale
link->lpm_policy, they sometimes end up triggering these conditions
and get aborted leading to LPM configuration failure.

Fix it by updating link->lpm_policy before issuing DIPM enable
commands.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarKyle McMartin <kyle@mcmartin.ca>
Cc: stable@kernel.org
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent f08dc1ac

drivers/ata/libata-eh.c

+14 −3
Original line number Diff line number Diff line
@@ -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,