[PATCH] libata: Pre UDMA EIDE PIO mode selection

I misread the spec when doing the original. I've tested the corrected
version with pre UDMA drives and it now picks the right modes. This is a
specific bug fix rather than an update or new feature item.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 99bae8369ab294b3983517a799b3e1738bcc762d..bc48d88fef5a3b912359618f1f9d9152449da07e 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1051,18 +1051,22 @@ static unsigned int ata_pio_modes(const struct ata_device *adev)
 {
        u16 modes;
 
-       /* Usual case. Word 53 indicates word 88 is valid */
-       if (adev->id[ATA_ID_FIELD_VALID] & (1 << 2)) {
+       /* Usual case. Word 53 indicates word 64 is valid */
+       if (adev->id[ATA_ID_FIELD_VALID] & (1 << 1)) {
                modes = adev->id[ATA_ID_PIO_MODES] & 0x03;
                modes <<= 3;
                modes |= 0x7;
                return modes;
        }
 
-       /* If word 88 isn't valid then Word 51 holds the PIO timing number
-          for the maximum. Turn it into a mask and return it */
-       modes = (2 << (adev->id[ATA_ID_OLD_PIO_MODES] & 0xFF)) - 1 ;
+       /* If word 64 isn't valid then Word 51 high byte holds the PIO timing
+          number for the maximum. Turn it into a mask and return it */
+       modes = (2 << ((adev->id[ATA_ID_OLD_PIO_MODES] >> 8) & 0xFF)) - 1 ;
        return modes;
+       /* But wait.. there's more. Design your standards by committee and
+          you too can get a free iordy field to process. However its the 
+          speeds not the modes that are supported... Note drivers using the
+          timing API will get this right anyway */
 }
 
 struct ata_exec_internal_arg {