ata_piix: disallow UDMA 133 on ICH5 & ICH7

There is another outstanding issue with ata_piix.c.  Intel has never
officially supported anything faster than PATA 100MB/s.

But, the ata_piix.c driver "define" the ICH5 & ICH7 as UDMA6 (aka 133MB/s)
capable.  [ Well, no one has probably noticed it before, because there is bug
in do_pata_set_dmamode...  Just look at
libata_atapiix_enable_real_udma133.patch and you'll see what wrong with it.  ]

Here are Intel's datasheets for the affected chipsets: ICH5 Datasheet:
http://www.intel.com/design/chipsets/datashts/252516.htm (See note on page
183: "...  the ICH5 supports reads at the maximum rate of 100MB/s.")

ICH7 Datasheet: http://www.intel.com/design/chipsets/datashts/307013.htm (See
first note on page 190: "...  the ICH7 supports reads at the maximum rate of
100MB/s.")

They are two different ways to deal with it:

- Either -

1. replace all ich_pata_133 with ich_pata_100.
   (libata_atapiix_disable_udma6.diff - diff from 2.6.22 )

- Or -

2. keep all ich_pata_133 and fix the bug in "do_pata_set_dmamode".
   (libata_atapiix_enable_real_udma133.patch - diff from 2.6.22) If there are
   any concerns about the safety of the patch patch:
   http://lkml.org/lkml/2007/7/6/292 (It was already tested by an Intel
   employee, but I guess a bit more user input is necessary here...  )

This patch implements 1.

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 03fe493026ebbfd375b9be1820929eef446e06b4..4b66b9e9638fe4e92fa9e0097993cfe0874ebad2 100644 (file)
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -123,7 +123,7 @@ enum {
        ich_pata_33             = 1,    /* ICH up to UDMA 33 only */
        ich_pata_66             = 2,    /* ICH up to 66 Mhz */
        ich_pata_100            = 3,    /* ICH up to UDMA 100 */
-       ich_pata_133            = 4,    /* ICH up to UDMA 133 */
+       /* ICH up to UDMA 133 is not supported */
        ich5_sata               = 5,
        ich6_sata               = 6,
        ich6_sata_ahci          = 7,
@@ -199,7 +199,7 @@ static const struct pci_device_id piix_pci_tbl[] = {
        { 0x8086, 0x24CA, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        { 0x8086, 0x24CB, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        /* Intel ICH5 */
-       { 0x8086, 0x24DB, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_133 },
+       { 0x8086, 0x24DB, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        /* C-ICH (i810E2) */
        { 0x8086, 0x245B, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        /* ESB (855GME/875P + 6300ESB) UDMA 100  */
@@ -207,7 +207,7 @@ static const struct pci_device_id piix_pci_tbl[] = {
        /* ICH6 (and 6) (i915) UDMA 100 */
        { 0x8086, 0x266F, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        /* ICH7/7-R (i945, i975) UDMA 100*/
-       { 0x8086, 0x27DF, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_133 },
+       { 0x8086, 0x27DF, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        { 0x8086, 0x269E, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
        /* ICH8 Mobile PATA Controller */
        { 0x8086, 0x2850, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich_pata_100 },
@@ -505,7 +505,7 @@ static struct ata_port_info piix_port_info[] = {
                .port_ops       = &ich_pata_ops,
        },
 
-       /* ich_pata_133: 4      ICH with full UDMA6 */
+       /* ich_pata_133: 4 - Not supported - */
        {
                .sht            = &piix_sht,
                .flags          = PIIX_PATA_FLAGS | PIIX_FLAG_CHECKINTR,