2009-04-23 07:57:59

by Chris Wright

[permalink] [raw]
Subject: [patch 070/100] hpt366: fix HPT370 DMA timeouts

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

From: Sergei Shtylyov <[email protected]>

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 <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
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, <[email protected]> or <[email protected]>
*/

@@ -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

static const char *quirk_drives[] = {