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: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Kyle McMartin <kyle@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---
drivers/ata/libata-eh.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
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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