2 files changed, 46 insertions, 29 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 2ab34dc97f6f..49cffb6094a3 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1494,6 +1494,7 @@ static int ata_hpa_resize(struct ata_device *dev)
 {
         struct ata_eh_context *ehc = &dev->link->eh_context;
         int print_info = ehc->i.flags & ATA_EHI_PRINTINFO;
+        bool unlock_hpa = ata_ignore_hpa || dev->flags & ATA_DFLAG_UNLOCK_HPA;
         u64 sectors = ata_id_n_sectors(dev->id);
         u64 native_sectors;
         int rc;
@@ -1510,7 +1511,7 @@ static int ata_hpa_resize(struct ata_device *dev)
                 /* If device aborted the command or HPA isn't going to
                  * be unlocked, skip HPA resizing.
                  */
-                if (rc == -EACCES || !ata_ignore_hpa) {
+                if (rc == -EACCES || !unlock_hpa) {
                         ata_dev_printk(dev, KERN_WARNING, "HPA support seems "
                                        "broken, skipping HPA handling\n");
                         dev->horkage |= ATA_HORKAGE_BROKEN_HPA;
@@ -1525,7 +1526,7 @@ static int ata_hpa_resize(struct ata_device *dev)
         dev->n_native_sectors = native_sectors;
 
         /* nothing to do? */
-        if (native_sectors <= sectors || !ata_ignore_hpa) {
+        if (native_sectors <= sectors || !unlock_hpa) {
                 if (!print_info || native_sectors == sectors)
                         return 0;
 
@@ -4186,36 +4187,51 @@ int ata_dev_revalidate(struct ata_device *dev, unsigned int new_class,
                 goto fail;
 
         /* verify n_sectors hasn't changed */
-        if (dev->class == ATA_DEV_ATA && n_sectors &&
-            dev->n_sectors != n_sectors) {
-                ata_dev_printk(dev, KERN_WARNING, "n_sectors mismatch "
-                               "%llu != %llu\n",
-                               (unsigned long long)n_sectors,
-                               (unsigned long long)dev->n_sectors);
-                /*
-                 * Something could have caused HPA to be unlocked
-                 * involuntarily.  If n_native_sectors hasn't changed
-                 * and the new size matches it, keep the device.
-                 */
-                if (dev->n_native_sectors == n_native_sectors &&
-                    dev->n_sectors > n_sectors &&
-                    dev->n_sectors == n_native_sectors) {
-                        ata_dev_printk(dev, KERN_WARNING,
-                                       "new n_sectors matches native, probably "
-                                       "late HPA unlock, continuing\n");
-                        /* keep using the old n_sectors */
-                        dev->n_sectors = n_sectors;
-                } else {
-                        /* restore original n_[native]_sectors and fail */
-                        dev->n_native_sectors = n_native_sectors;
-                        dev->n_sectors = n_sectors;
-                        rc = -ENODEV;
-                        goto fail;
-                }
+        if (dev->class != ATA_DEV_ATA || !n_sectors ||
+            dev->n_sectors == n_sectors)
+                return 0;
+
+        /* n_sectors has changed */
+        ata_dev_printk(dev, KERN_WARNING, "n_sectors mismatch %llu != %llu\n",
+                       (unsigned long long)n_sectors,
+                       (unsigned long long)dev->n_sectors);
+
+        /*
+         * Something could have caused HPA to be unlocked
+         * involuntarily.  If n_native_sectors hasn't changed and the
+         * new size matches it, keep the device.
+         */
+        if (dev->n_native_sectors == n_native_sectors &&
+            dev->n_sectors > n_sectors && dev->n_sectors == n_native_sectors) {
+                ata_dev_printk(dev, KERN_WARNING,
+                               "new n_sectors matches native, probably "
+                               "late HPA unlock, continuing\n");
+                /* keep using the old n_sectors */
+                dev->n_sectors = n_sectors;
+                return 0;
         }
 
-        return 0;
+        /*
+         * Some BIOSes boot w/o HPA but resume w/ HPA locked.  Try
+         * unlocking HPA in those cases.
+         *
+         * https://bugzilla.kernel.org/show_bug.cgi?id=15396
+         */
+        if (dev->n_native_sectors == n_native_sectors &&
+            dev->n_sectors < n_sectors && n_sectors == n_native_sectors &&
+            !(dev->horkage & ATA_HORKAGE_BROKEN_HPA)) {
+                ata_dev_printk(dev, KERN_WARNING,
+                               "old n_sectors matches native, probably "
+                               "late HPA lock, will try to unlock HPA\n");
+                /* try unlocking HPA */
+                dev->flags |= ATA_DFLAG_UNLOCK_HPA;
+                rc = -EIO;
+        } else
+                rc = -ENODEV;
 
+        /* restore original n_[native_]sectors and fail */
+        dev->n_native_sectors = n_native_sectors;
+        dev->n_sectors = n_sectors;
  fail:
         ata_dev_printk(dev, KERN_ERR, "revalidation failed (errno=%d)\n", rc);
         return rc;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index f8ea71e6d0e2..b2f2003b92e5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -146,6 +146,7 @@ enum {
         ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
         ATA_DFLAG_DUBIOUS_XFER  = (1 << 16), /* data transfer not verified */
         ATA_DFLAG_NO_UNLOAD     = (1 << 17), /* device doesn't support unload */
+        ATA_DFLAG_UNLOCK_HPA    = (1 << 18), /* unlock HPA */
         ATA_DFLAG_INIT_MASK     = (1 << 24) - 1,
 
         ATA_DFLAG_DETACH        = (1 << 24),