Commit 50a99018 authored by Alan Cox's avatar Alan Cox Committed by Jeff Garzik
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libata-core: Document some limits/assumptions about ID_ATA 



Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent baf4fdfa

drivers/ata/libata-core.c

+8 −2
Original line number Diff line number Diff line
@@ -1618,6 +1618,9 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev) 
 *	devices.  This function also issues ATA_CMD_INIT_DEV_PARAMS

 *	for pre-ATA4 drives.

 *

 *	FIXME: ATA_CMD_ID_ATA is optional for early drives and right

 *	now we abort if we hit that case. 

 *

 *	LOCKING:

 *	Kernel thread context (may sleep)

 *
@@ -1745,10 +1748,13 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class, 
		/*

		 * The exact sequence expected by certain pre-ATA4 drives is:

		 * SRST RESET

		 * IDENTIFY

		 * INITIALIZE DEVICE PARAMETERS

		 * IDENTIFY (optional in early ATA)

		 * INITIALIZE DEVICE PARAMETERS (later IDE and ATA)

		 * anything else..

		 * Some drives were very specific about that exact sequence.

		 *

		 * Note that ATA4 says lba is mandatory so the second check

		 * shoud never trigger.

		 */

		if (ata_id_major_version(id) < 4 || !ata_id_has_lba(id)) {

			err_mask = ata_dev_init_params(dev, id[3], id[6]);