libata: force hardreset if link is in powersave mode

libata: force hardreset if link is in powersave mode

[Tejun Heo]

Inhibiting link PM mode doesn't bring the link back online if it's
already in powersave mode.  If SRST is used in these cases, libata EH
thinks that the link is offline and fails detection.  Force hardreset
if link is in powersave mode.

Signed-off-by: Tejun Heo <htejun@gmail.com>
---
Patch for -stable only.  Devel branch now uses hardreset by default so
this type of promotion logic isn't necessary anymore.

 drivers/ata/libata-core.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

Index: linux-2.6.25/drivers/ata/libata-core.c
===================================================================
--- linux-2.6.25.orig/drivers/ata/libata-core.c
+++ linux-2.6.25/drivers/ata/libata-core.c
@@ -3960,6 +3960,7 @@ int ata_std_prereset(struct ata_link *li
 	struct ata_port *ap = link->ap;
 	struct ata_eh_context *ehc = &link->eh_context;
 	const unsigned long *timing = sata_ehc_deb_timing(ehc);
+	u32 sstatus;
 	int rc;
 
 	/* handle link resume */
@@ -3973,6 +3974,17 @@ int ata_std_prereset(struct ata_link *li
 	if (ap->flags & ATA_FLAG_PMP)
 		ehc->i.action |= ATA_EH_HARDRESET;
 
+	/* if link powersave is on, force hardreset */
+	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0) {
+		u8 ipm = sstatus >> 8;
+
+		if (ipm == 2 || ipm == 6) {
+			ata_link_printk(link, KERN_INFO, "link in powersave "
+				"mode (ipm=%d), forcing hardreset\n", ipm);
+			ehc->i.action |= ATA_EH_HARDRESET;
+		}
+	}
+
 	/* if we're about to do hardreset, nothing more to do */
 	if (ehc->i.action & ATA_EH_HARDRESET)
 		return 0;

patch libata-force-hardreset-if-link-is-in-powersave-mode.patch added to 2.6.25-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

     Subject: libata: force hardreset if link is in powersave mode

to the 2.6.25-stable tree.  Its filename is

     libata-force-hardreset-if-link-is-in-powersave-mode.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From stable-bounces@linux.kernel.org Thu May 15 06:15:27 2008
From: Tejun Heo <htejun@gmail.com>
Date: Thu, 15 May 2008 22:14:57 +0900
Subject: libata: force hardreset if link is in powersave mode
To: Jeff Garzik <jeff@garzik.org>, IDE/ATA development list <linux-ide@vger.kernel.org>, stable@kernel.org
Cc: matthieu.castet@parrot.com
Message-ID: <482C3751.8030206@gmail.com>

From: Tejun Heo <htejun@gmail.com>

Inhibiting link PM mode doesn't bring the link back online if it's
already in powersave mode.  If SRST is used in these cases, libata EH
thinks that the link is offline and fails detection.  Force hardreset
if link is in powersave mode.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/ata/libata-core.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3947,6 +3947,7 @@ int ata_std_prereset(struct ata_link *li
 	struct ata_port *ap = link->ap;
 	struct ata_eh_context *ehc = &link->eh_context;
 	const unsigned long *timing = sata_ehc_deb_timing(ehc);
+	u32 sstatus;
 	int rc;
 
 	/* handle link resume */
@@ -3960,6 +3961,17 @@ int ata_std_prereset(struct ata_link *li
 	if (ap->flags & ATA_FLAG_PMP)
 		ehc->i.action |= ATA_EH_HARDRESET;
 
+	/* if link powersave is on, force hardreset */
+	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0) {
+		u8 ipm = sstatus >> 8;
+
+		if (ipm == 2 || ipm == 6) {
+			ata_link_printk(link, KERN_INFO, "link in powersave "
+				"mode (ipm=%d), forcing hardreset\n", ipm);
+			ehc->i.action |= ATA_EH_HARDRESET;
+		}
+	}
+
 	/* if we're about to do hardreset, nothing more to do */
 	if (ehc->i.action & ATA_EH_HARDRESET)
 		return 0;


Patches currently in stable-queue which might be from htejun@gmail.com are

queue-2.6.25/libata-force-hardreset-if-link-is-in-powersave-mode.patch