[patch 39/88] hpt366: fix HPT370 DMA timeouts

Greg KH
2009-04-30T17:24:45Z

[-- Attachment #1: 0069-hpt366-fix-HPT370-DMA-timeouts.patch --]
[-- Type: text/plain, Size: 1608 bytes --]

2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Sergei Shtylyov <sshtylyov@ru.mvista.com>

upstream commit: c018f1ee5cf81e58b93d9e93a2ee39cad13dc1ac

The big driver change in 2.4.19-rc1 introduced a regression for many HPT370[A]
chips -- DMA stopped to work completely, only causing endless timeouts...

The culprit has been identified (at last!): it turned to be the code resetting
the DMA state machine before each transfer. Stop doing it now as this counter-
measure has clearly caused more harm than good.

This should fix the kernel.org bug #7703.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/ide/hpt366.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/ide/hpt366.c
+++ b/drivers/ide/hpt366.c
@@ -114,6 +114,8 @@
* the register setting lists into the table indexed by the clock selected
* - set the correct hwif->ultra_mask for each individual chip
* - add Ultra and MW DMA mode filtering for the HPT37[24] based SATA cards
+ * - stop resetting HPT370's state machine before each DMA transfer as that has
+ * caused more harm than good
* Sergei Shtylyov, <sshtylyov@ru.mvista.com> or <source@mvista.com>
*/

@@ -133,7 +135,7 @@
#define DRV_NAME "hpt366"

/* various tuning parameters */
-#define HPT_RESET_STATE_ENGINE
+#undef HPT_RESET_STATE_ENGINE
#undef HPT_DELAY_INTERRUPT
#define HPT_SERIALIZE_IO 0