From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Date: Mon, 9 Jan 2006 17:14:40 +0000 (+0000)
Subject: [PATCH] libata: Pre UDMA EIDE PIO mode selection
X-Git-Tag: v2.6.16-rc2~365^2~5
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ffa29456cd316a5394cdd489de5af3bf87d3c485;p=linux-2.6

[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 99bae8369a..bc48d88fef 100644
--- 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 {