libata: quickly trigger SATA SPD down after debouncing failed

Debouncing failure is a good indicator of basic link problem.  Use
-EPIPE to indicate debouncing failure and make ata_eh_reset() invoke
sata_down_spd_limit() if the error occurs during reset.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 5 insertions, 3 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c325b7a4246a..05922e9f4fad 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3267,9 +3267,11 @@ int sata_phy_debounce(struct ata_port *ap, const unsigned long *params,
                 last = cur;
                 last_jiffies = jiffies;
 
-                /* check deadline */
+                /* Check deadline.  If debouncing failed, return
+                 * -EPIPE to tell upper layer to lower link speed.
+                 */
                 if (time_after(jiffies, deadline))
-                        return -EBUSY;
+                        return -EPIPE;
         }
 }
 
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 183eaf466d4f..1a4397ae9e48 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1790,7 +1790,7 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
                         schedule_timeout_uninterruptible(delta);
                 }
 
-                if (reset == hardreset &&
+                if (rc == -EPIPE ||
                     try == ARRAY_SIZE(ata_eh_reset_timeouts) - 1)
                         sata_down_spd_limit(ap);
                 if (hardreset)