(S)ATA drives can be configured for "power-up in standby",
a mode whereby a specific "spin up now!" command is required
before the first media access.

Currently, a drive with this feature enabled can not be used at all
with libata, and once in this mode, the drive becomes a doorstop.

The older drivers/ide subsystem at least enumerates the drive,
so that it can be woken up after the fact from a userspace HDIO_*
command, but not libata.

This patch adds support to libata for the "power-up in standby"
mode where a "spin up now!" command (SET_FEATURES) is needed.
With this, libata will recognize such drives, spin them up,
and then re-IDENTIFY them if necessary to get a full/complete
set of drive features data.

Drives in this state are determined by looking for
special values in id[2], as documented in the current ATA specs.

Signed-off-by: Mark Lord <[EMAIL PROTECTED]>
---
diff -u --recursive --new-file 
--exclude-from=linux-2.6.20//Documentation/dontdiff 
linux-2.6.20/drivers/ata/libata-core.c linux/drivers/ata/libata-core.c
--- linux-2.6.20/drivers/ata/libata-core.c      2007-02-04 13:44:54.000000000 
-0500
+++ linux/drivers/ata/libata-core.c     2007-02-22 15:19:41.000000000 -0500
@@ -1453,6 +1453,7 @@
        struct ata_taskfile tf;
        unsigned int err_mask = 0;
        const char *reason;
+       int tried_spinup = 0;
        int rc;

        if (ata_msg_ctl(ap))
@@ -1460,7 +1461,6 @@
                               __FUNCTION__, ap->id, dev->devno);

        ata_dev_select(ap, dev->devno, 1, 1); /* select device 0/1 */
-
 retry:
        ata_tf_init(dev, &tf);

@@ -1508,6 +1508,32 @@
                        goto err_out;
        }

+       if (!tried_spinup && (id[2] == 0x37c8 || id[2] == 0x738c)) {
+               tried_spinup = 1;
+               /*
+                * Drive powered-up in standby mode, and requires a specific
+                * SET_FEATURES spin-up subcommand before it will accept
+                * anything other than the original IDENTIFY command.
+                */
+               ata_tf_init(dev, &tf);
+               tf.command = ATA_CMD_SET_FEATURES;
+               tf.feature = SETFEATURES_SPINUP;
+               tf.protocol = ATA_PROT_NODATA;
+               tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+               err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+               if (err_mask) {
+                       rc = -EIO;
+                       reason = "SPINUP failed";
+                       goto err_out;
+               }
+               /*
+                * If the drive initially returned incomplete IDENTIFY info,
+                * we now must reissue the IDENTIFY command.
+                */
+               if (id[2] == 0x37c8)
+                       goto retry;
+       }
+
        if ((flags & ATA_READID_POSTRESET) && class == ATA_DEV_ATA) {
                /*
                 * The exact sequence expected by certain pre-ATA4 drives is:
diff -u --recursive --new-file 
--exclude-from=linux-2.6.20//Documentation/dontdiff 
linux-2.6.20/include/linux/ata.h linux/include/linux/ata.h
--- linux-2.6.20/include/linux/ata.h    2007-02-04 13:44:54.000000000 -0500
+++ linux/include/linux/ata.h   2007-02-22 13:52:45.000000000 -0500
@@ -190,6 +190,8 @@
        SETFEATURES_WC_ON       = 0x02, /* Enable write cache */
        SETFEATURES_WC_OFF      = 0x82, /* Disable write cache */

+       SETFEATURES_SPINUP      = 0x07, /* Spin-up drive */
+
        /* ATAPI stuff */
        ATAPI_PKT_DMA           = (1 << 0),
        ATAPI_DMADIR            = (1 << 2),       /* ATAPI data dir:
-
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