libata: Implement ATA_FLAG_NO_DIPM and apply it to mcp65

NVIDIA mcp65 familiy of controllers cause command timeouts when DIPM
is used.  Implement ATA_FLAG_NO_DIPM and apply it.

This problem was reported by Stefan Bader in the following thread.

 http://thread.gmane.org/gmane.linux.ide/48841

stable: applicable to 2.6.37 and 38.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stefan Bader <stefan.bader@canonical.com>
Cc: stable@kernel.org
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 88cd22fa65cd..f26f2fe3480a 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -3316,6 +3316,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
         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;
+        bool no_dipm = ap->flags & ATA_FLAG_NO_DIPM;
         unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
         unsigned int err_mask;
         int rc;
@@ -3332,7 +3333,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
          */
         ata_for_each_dev(dev, link, ENABLED) {
                 bool hipm = ata_id_has_hipm(dev->id);
-                bool dipm = ata_id_has_dipm(dev->id);
+                bool dipm = ata_id_has_dipm(dev->id) && !no_dipm;
 
                 /* find the first enabled and LPM enabled devices */
                 if (!link_dev)
@@ -3389,7 +3390,8 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_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)) {
+                if (policy == ATA_LPM_MIN_POWER && !no_dipm &&
+                    ata_id_has_dipm(dev->id)) {
                         err_mask = ata_dev_set_feature(dev,
                                         SETFEATURES_SATA_ENABLE, SATA_DIPM);
                         if (err_mask && err_mask != AC_ERR_DEV) {