indistinguishable devices with broken and unbroken firmware

@@ -1430,7 +1430,7 @@
 		"DataStor",
 		"USB4500 FW1.04",
 		US_SC_DEVICE, US_PR_DEVICE, NULL,
-		US_FL_FIX_CAPACITY),
+		US_FL_CAPACITY_HEURISTICS),
 
 /* Control/Bulk transport for all SubClass values */
 USUAL_DEV(US_SC_RBC, US_PR_CB, USB_US_TYPE_STOR),

@@ -170,6 +170,12 @@
 		if (us->flags & US_FL_FIX_CAPACITY)
 			sdev->fix_capacity = 1;
 
+		/* A few disks have two indistinguishable version, one of
+		 * which reports the correct capacity and the other does not.
+		 * The sd driver has to guess which is the case. */
+		if (us->flags & US_FL_CAPACITY_HEURISTICS)
+			sdev->guess_capacity = 1;
+
 		/* Some devices report a SCSI revision level above 2 but are
 		 * unable to handle the REPORT LUNS command (for which
 		 * support is mandatory at level 3).  Since we already have

@@ -1273,6 +1273,13 @@
 	if (sdp->fix_capacity)
 		--sdkp->capacity;
 
+	/* Some devices have version which report the correct sizes
+	 * and others which do not. We guess size according to a heuristic
+	 * and err on the side of lowering the capacity. */
+	if (sdp->guess_capacity)
+		if (sdkp->capacity & 0x01) /* odd sizes are odd */
+			--sdkp->capacity;
+
 got_data:
 	if (sector_size == 0) {
 		sector_size = 512;

@@ -46,7 +46,9 @@
 	US_FLAG(MAX_SECTORS_64,	0x00000400)			\
 		/* Sets max_sectors to 64    */			\
 	US_FLAG(IGNORE_DEVICE,	0x00000800)			\
-		/* Don't claim device */
+		/* Don't claim device */			\
+	US_FLAG(CAPACITY_HEURISTICS,	0x00001000)		\
+		/* sometimes sizes is too big */
 
 #define US_FLAG(name, value)	US_FL_##name = value ,
 enum { US_DO_ALL_FLAGS };

@@ -122,6 +122,7 @@
 	unsigned no_uld_attach:1; /* disable connecting to upper level drivers */
 	unsigned select_no_atn:1;
 	unsigned fix_capacity:1;	/* READ_CAPACITY is too high by 1 */
+	unsigned guess_capacity:1;	/* READ_CAPACITY might be too high by 1 */
 	unsigned retry_hwerror:1;	/* Retry HARDWARE_ERROR */
 
 	unsigned int device_blocked;	/* Device returned QUEUE_FULL. */