[PATCH] libata: clear only affected flags during ata_dev_configure()

ata_dev_configure() should not clear dynamic device flags determined
elsewhere.  Lower eight bits are reserved for feature flags, define
ATA_DFLAG_CFG_MASK and clear only those bits before configuring
device.  Without this patch, ATA_DFLAG_PIO gets turned off during
revalidation making PIO mode unuseable.

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

2 files changed, 2 insertions, 1 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 53226b16355..985283cbcbd 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1241,7 +1241,7 @@ static int ata_dev_configure(struct ata_port *ap, struct ata_device *dev,
                        id[84], id[85], id[86], id[87], id[88]);
 
         /* initialize to-be-configured parameters */
-        dev->flags = 0;
+        dev->flags &= ~ATA_DFLAG_CFG_MASK;
         dev->max_sectors = 0;
         dev->cdb_len = 0;
         dev->n_sectors = 0;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 890262f44d0..cbbc821fe22 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -122,6 +122,7 @@ enum {
         /* struct ata_device stuff */
         ATA_DFLAG_LBA           = (1 << 0), /* device supports LBA */
         ATA_DFLAG_LBA48         = (1 << 1), /* device supports LBA48 */
+        ATA_DFLAG_CFG_MASK      = (1 << 8) - 1,
 
         ATA_DFLAG_PIO           = (1 << 8), /* device currently in PIO mode */