[libata] pata_legacy: for VLB 32bit PIO don't try tricks with slop
These devices are generally used with ATA anyway and it seems that some
ATAPI will need us to issue the right number of words. Therefore as we
can't switch mid burst on VLB devices we should only use 32bit I/O for
suitable block sizes.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
index 6c1d778..e3bc1b4 100644
--- a/drivers/ata/pata_legacy.c
+++ b/drivers/ata/pata_legacy.c
@@ -283,9 +283,10 @@
static unsigned int pdc_data_xfer_vlb(struct ata_device *dev,
unsigned char *buf, unsigned int buflen, int rw)
{
- if (ata_id_has_dword_io(dev->id)) {
+ int slop = buflen & 3;
+ /* 32bit I/O capable *and* we need to write a whole number of dwords */
+ if (ata_id_has_dword_io(dev->id) && (slop == 0 || slop == 3)) {
struct ata_port *ap = dev->link->ap;
- int slop = buflen & 3;
unsigned long flags;
local_irq_save(flags);
@@ -735,7 +736,7 @@
struct ata_port *ap = adev->link->ap;
int slop = buflen & 3;
- if (ata_id_has_dword_io(adev->id)) {
+ if (ata_id_has_dword_io(adev->id) && (slop == 0 || slop == 3)) {
if (rw == WRITE)
iowrite32_rep(ap->ioaddr.data_addr, buf, buflen >> 2);
else