[PATCH] SCSI: make DV check device capabilities

the SPI transport class DV should check the data we derive from the
inquiry to see if the device is capable of supporting wide/sync before
trying to validate the settings.

drivers/scsi/scsi_transport_spi.c

@@ -490,7 +490,7 @@ spi_dv_device_internal(struct scsi_request *sreq, u8 *buffer)
 	}
 
 	/* test width */
-	if (i->f->set_width) {
+	if (i->f->set_width && sdev->wdtr) {
 		i->f->set_width(sdev, 1);
 
 		if (!spi_dv_device_compare_inquiry(sreq, buffer,
@@ -504,6 +504,10 @@ spi_dv_device_internal(struct scsi_request *sreq, u8 *buffer)
 	if (!i->f->set_period)
 		return;
 
+	/* device can't handle synchronous */
+	if(!sdev->ppr && !sdev->sdtr)
+		return;
+
 	/* now set up to the maximum */
 	DV_SET(offset, 255);
 	DV_SET(period, 1);