ATA devices in SLEEP mode don't respond to any commands.  SRST is
necessary to wake it up.  Till now, when a command is issued to a
device in SLEEP mode, the command times out, which makes EH reset the
device and retry the command after that, causing a long delay.

This patch makes libata track SLEEP state and issue SRST automatically
if a command is about to be issued to a device in SLEEP.

Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
Cc: Bruce Allen <[EMAIL PROTECTED]>
Cc: Andrew Paprocki <[EMAIL PROTECTED]>
---
 drivers/ata/libata-core.c |   12 ++++++++++++
 drivers/ata/libata-eh.c   |    4 +++-
 include/linux/ata.h       |    1 +
 include/linux/libata.h    |    1 +
 4 files changed, 17 insertions(+), 1 deletion(-)

Index: work/include/linux/ata.h
===================================================================
--- work.orig/include/linux/ata.h
+++ work/include/linux/ata.h
@@ -179,6 +179,7 @@ enum {
        ATA_CMD_VERIFY          = 0x40,
        ATA_CMD_VERIFY_EXT      = 0x42,
        ATA_CMD_STANDBYNOW1     = 0xE0,
+       ATA_CMD_SLEEP           = 0xE6,
        ATA_CMD_IDLEIMMEDIATE   = 0xE1,
        ATA_CMD_INIT_DEV_PARAMS = 0x91,
        ATA_CMD_READ_NATIVE_MAX = 0xF8,
Index: work/include/linux/libata.h
===================================================================
--- work.orig/include/linux/libata.h
+++ work/include/linux/libata.h
@@ -145,6 +145,7 @@ enum {
        ATA_DFLAG_PIO           = (1 << 12), /* device limited to PIO mode */
        ATA_DFLAG_NCQ_OFF       = (1 << 13), /* device limited to non-NCQ mode 
*/
        ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
+       ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
        ATA_DFLAG_INIT_MASK     = (1 << 16) - 1,
 
        ATA_DFLAG_DETACH        = (1 << 16),
Index: work/drivers/ata/libata-core.c
===================================================================
--- work.orig/drivers/ata/libata-core.c
+++ work/drivers/ata/libata-core.c
@@ -5553,6 +5553,10 @@ void __ata_qc_complete(struct ata_queued
                case ATA_CMD_SET_MULTI: /* multi_count changed */
                        eh_action |= ATA_EH_REVALIDATE;
                        break;
+
+               case ATA_CMD_SLEEP:
+                       qc->dev->flags |= ATA_DFLAG_SLEEPING;
+                       break;
                }
 
                if (unlikely(eh_action) && ap->ops->error_handler) {
@@ -5757,6 +5761,14 @@ void ata_qc_issue(struct ata_queued_cmd 
                qc->flags &= ~ATA_QCFLAG_DMAMAP;
        }
 
+       /* if device is sleeping, schedule softreset and abort the link */
+       if (unlikely(qc->dev->flags & ATA_DFLAG_SLEEPING)) {
+               link->eh_info.action |= ATA_EH_SOFTRESET;
+               ata_ehi_push_desc(&link->eh_info, "waking up from sleep");
+               ata_link_abort(link);
+               return;
+       }
+
        ap->ops->qc_prep(qc);
 
        qc->err_mask |= ap->ops->qc_issue(qc);
Index: work/drivers/ata/libata-eh.c
===================================================================
--- work.orig/drivers/ata/libata-eh.c
+++ work/drivers/ata/libata-eh.c
@@ -2207,9 +2207,11 @@ int ata_eh_reset(struct ata_link *link, 
                ata_link_for_each_dev(dev, link) {
                        /* After the reset, the device state is PIO 0
                         * and the controller state is undefined.
-                        * Record the mode.
+                        * Reset also wakes up drives from sleeping
+                        * mode.
                         */
                        dev->pio_mode = XFER_PIO_0;
+                       dev->flags &= ~ATA_DFLAG_SLEEPING;
 
                        if (ata_link_offline(link))
                                continue;
-
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