[PATCH] ata: ata_id_is_ssd() bugfix

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

We need to explicitly check for major and minor version
of supported ATA spec as earlier revisions used word 217
for different purposes.

[ The issue was originally spotted by Alan Cox. ]

This patch fixes regression introduced by:
commit 8bff7c6b0f63c7ee9c5e3a076338d74125b8debb
("libata: set queue SSD flag for SSD devices").

Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
somebody owe me one for going through all these spec drafts... ;)

 include/linux/ata.h |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Index: b/include/linux/ata.h
===================================================================
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -75,6 +75,7 @@ enum {
 	ATA_ID_EIDE_PIO_IORDY	= 68,
 	ATA_ID_QUEUE_DEPTH	= 75,
 	ATA_ID_MAJOR_VER	= 80,
+	ATA_ID_MINOR_VER	= 81,
 	ATA_ID_COMMAND_SET_1	= 82,
 	ATA_ID_COMMAND_SET_2	= 83,
 	ATA_ID_CFSSE		= 84,
@@ -743,7 +744,12 @@ static inline int ata_id_is_cfa(const u1
 
 static inline int ata_id_is_ssd(const u16 *id)
 {
-	return id[ATA_ID_ROT_SPEED] == 0x01;
+	/* ATA8-ACS version 4c or higher (=> 4c or 6 at the moment) */
+	if (ata_id_major_version(id) >= 8 &&
+	    (id[ATA_ID_MINOR_VER] == 0x39 || id[ATA_ID_MINOR_VER] == 0x28) &&
+	    id[ATA_ID_ROT_SPEED] == 0x01)
+		return 1;
+	return 0;
 }
 
 static inline int ata_drive_40wire(const u16 *dev_id)