[PATCH] libata: always use polling IDENTIFY

libata switched to IRQ-driven IDENTIFY when IRQ-driven PIO was
introduced.  This has caused a lot of problems including device
misdetection and phantom device.

ATA_FLAG_DETECT_POLLING was added recently to selectively use polling
IDENTIFY on problemetic drivers but many controllers and devices are
affected by this problem and trying to adding ATA_FLAG_DETECT_POLLING
for each such case is diffcult and not very rewarding.

This patch makes libata always use polling IDENTIFY.  This is
consistent with libata's original behavior and drivers/ide's behavior.

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

5 files changed, 5 insertions, 17 deletions

diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 788a269206e6..a2d84f7cf2bc 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -105,9 +105,8 @@ enum {
         PIIX_FLAG_AHCI          = (1 << 27), /* AHCI possible */
         PIIX_FLAG_CHECKINTR     = (1 << 28), /* make sure PCI INTx enabled */
 
-        PIIX_PATA_FLAGS         = ATA_FLAG_SLAVE_POSS | ATA_FLAG_DETECT_POLLING,
-        PIIX_SATA_FLAGS         = ATA_FLAG_SATA | PIIX_FLAG_CHECKINTR |
-                                  ATA_FLAG_DETECT_POLLING,
+        PIIX_PATA_FLAGS         = ATA_FLAG_SLAVE_POSS,
+        PIIX_SATA_FLAGS         = ATA_FLAG_SATA | PIIX_FLAG_CHECKINTR,
 
         /* combined mode.  if set, PATA is channel 0.
          * if clear, PATA is channel 1.
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 883276388207..f8ec3896b793 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1473,16 +1473,12 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
         }
 
         tf.protocol = ATA_PROT_PIO;
-
-        /* presence detection using polling IDENTIFY? */
-        if (flags & ATA_READID_DETECT)
-                tf.flags |= ATA_TFLAG_POLLING;
+        tf.flags |= ATA_TFLAG_POLLING; /* for polling presence detection */
 
         err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
                                      id, sizeof(id[0]) * ATA_ID_WORDS);
         if (err_mask) {
-                if ((flags & ATA_READID_DETECT) &&
-                    (err_mask & AC_ERR_NODEV_HINT)) {
+                if (err_mask & AC_ERR_NODEV_HINT) {
                         DPRINTK("ata%u.%d: NODEV after polling detection\n",
                                 ap->id, dev->devno);
                         return -ENOENT;
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 2aad7b79d6dd..76a85dfb7307 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1692,9 +1692,6 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
                            ata_class_enabled(ehc->classes[dev->devno])) {
                         dev->class = ehc->classes[dev->devno];
 
-                        if (ap->flags & ATA_FLAG_DETECT_POLLING)
-                                readid_flags |= ATA_READID_DETECT;
-
                         rc = ata_dev_read_id(dev, &dev->class, readid_flags,
                                              dev->id);
                         if (rc == 0) {
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 1ff3f59504c9..107b2b565229 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -42,8 +42,6 @@ struct ata_scsi_args {
 enum {
         /* flags for ata_dev_read_id() */
         ATA_READID_POSTRESET    = (1 << 0), /* reading ID after reset */
-        ATA_READID_DETECT       = (1 << 1), /* perform presence detection
-                                             * using polling IDENTIFY */
 };
 
 extern struct workqueue_struct *ata_aux_wq;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 8b57b6a806cc..202283b5df96 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -176,9 +176,7 @@ enum {
         ATA_FLAG_SKIP_D2H_BSY   = (1 << 12), /* can't wait for the first D2H
                                               * Register FIS clearing BSY */
         ATA_FLAG_DEBUGMSG       = (1 << 13),
-        ATA_FLAG_DETECT_POLLING = (1 << 14), /* detect device presence by
-                                              * polling IDENTIFY */
-        ATA_FLAG_SETXFER_POLLING= (1 << 15), /* use polling for SETXFER */
+        ATA_FLAG_SETXFER_POLLING= (1 << 14), /* use polling for SETXFER */
 
         /* The following flag belongs to ap->pflags but is kept in
          * ap->flags because it's referenced in many LLDs and will be