[PATCH] libata: improve handling of diagostic fail (and hardware that misreports it)

Our ATA probe code checks that a device is not reporting a diagnostic
failure during start up. Unfortunately at least one device seems to like
doing this - the Gigabyte iRAM.

This is only done for the master right now (which is fine for the iRAM
as it is SATA), as with PATA some combinations of ATAPI device seem to
fool the check into seeing a drive that isn't there if it is applied to
the slave.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

@@ -616,8 +616,11 @@ ata_dev_try_classify(struct ata_port *ap, unsigned int device, u8 *r_err)
 	if (r_err)
 		*r_err = err;
 
-	/* see if device passed diags */
-	if (err == 1)
+	/* see if device passed diags: if master then continue and warn later */
+	if (err == 0 && device == 0)
+		/* diagnostic fail : do nothing _YET_ */
+		ap->device[device].horkage |= ATA_HORKAGE_DIAGNOSTIC;
+	else if (err == 1)
 		/* do nothing */ ;
 	else if ((device == 0) && (err == 0x81))
 		/* do nothing */ ;
@@ -1523,6 +1526,18 @@ int ata_dev_configure(struct ata_device *dev, int print_info)
 				       cdb_intr_string);
 	}
 
+	if (dev->horkage & ATA_HORKAGE_DIAGNOSTIC) {
+		/* Let the user know. We don't want to disallow opens for
+		   rescue purposes, or in case the vendor is just a blithering
+		   idiot */
+                if (print_info) {
+			ata_dev_printk(dev, KERN_WARNING,
+"Drive reports diagnostics failure. This may indicate a drive\n");
+			ata_dev_printk(dev, KERN_WARNING,
+"fault or invalid emulation. Contact drive vendor for information.\n");
+		}
+	}
+
 	ata_set_port_max_cmd_len(ap);
 
 	/* limit bridge transfers to udma5, 200 sectors */

include/linux/libata.h

@@ -289,6 +289,11 @@ enum {
 	 * most devices.
 	 */
 	ATA_SPINUP_WAIT		= 8000,
+	
+	/* Horkage types. May be set by libata or controller on drives
+	   (some horkage may be drive/controller pair dependant */
+
+	ATA_HORKAGE_DIAGNOSTIC	= (1 << 0),	/* Failed boot diag */
 };
 
 enum hsm_task_states {
@@ -476,6 +481,7 @@ struct ata_device {
 
 	/* error history */
 	struct ata_ering	ering;
+	unsigned int		horkage;	/* List of broken features */
 };
 
 /* Offset into struct ata_device.  Fields above it are maintained