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 03fe493..4b66b9e 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -123,7 +123,7 @@
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 @@
{ 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 @@
/* 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 @@
.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,