[PATCH] libata: Don't believe bogus claims in the older PIO mode register
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index dce6565..ad8e2c6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -870,7 +870,11 @@
* the PIO timing number for the maximum. Turn it into
* a mask.
*/
- pio_mask = (2 << (id[ATA_ID_OLD_PIO_MODES] & 0xFF)) - 1 ;
+ u8 mode = id[ATA_ID_OLD_PIO_MODES] & 0xFF;
+ if (mode < 5) /* Valid PIO range */
+ pio_mask = (2 << mode) - 1;
+ else
+ pio_mask = 1;
/* But wait.. there's more. Design your standards by
* committee and you too can get a free iordy field to