Commit 169439c2 authored by Mark Lord's avatar Mark Lord Committed by Jeff Garzik
Browse files

libata: Handle drives that require a spin-up command before first access 



(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: default avatarMark Lord <mlord@pobox.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 1e999736

drivers/ata/libata-core.c

+27 −1
Original line number Diff line number Diff line
@@ -1649,13 +1649,13 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class, 
	struct ata_taskfile tf;

	unsigned int err_mask = 0;

	const char *reason;

	int tried_spinup = 0;

	int rc;



	if (ata_msg_ctl(ap))

		ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER\n", __FUNCTION__);



	ata_dev_select(ap, dev->devno, 1, 1); /* select device 0/1 */



 retry:

	ata_tf_init(dev, &tf);
@@ -1712,6 +1712,32 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class, 
			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:

include/linux/ata.h

+2 −0
Original line number Diff line number Diff line
@@ -202,6 +202,8 @@ enum { 
	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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