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opti621: disable read prefetch
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This fixes 2.6.25 regression (kernel.org bugzilla bug #10723) caused by:

commit 912fb29
Author: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date:   Fri Oct 19 00:30:11 2007 +0200

    opti621: always tune PIO
...

Based on a bugreport from Juergen Kosel & inspired by pata_opti.c code.

Bisected-by: Juergen Kosel <juergen.kosel@gmx.de>
Tested-by: Juergen Kosel <juergen.kosel@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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Bartlomiej Zolnierkiewicz committed Jun 15, 2008
1 parent 7775c97 commit 62128b2
Showing 1 changed file with 2 additions and 13 deletions.
15 changes: 2 additions & 13 deletions drivers/ide/pci/opti621.c
Original file line number Diff line number Diff line change
@@ -102,18 +102,6 @@
* address: 50 ns, data: 50 ns, recovery: 100 ns.
*/

/* #define READ_PREFETCH 0 */
/* Uncomment for disable read prefetch.
* There is some readprefetch capatibility in hdparm,
* but when I type hdparm -P 1 /dev/hda, I got errors
* and till reset drive is inaccessible.
* This (hw) read prefetch is safe on my drive.
*/

#ifndef READ_PREFETCH
#define READ_PREFETCH 0x40 /* read prefetch is enabled */
#endif /* else read prefetch is disabled */

#define READ_REG 0 /* index of Read cycle timing register */
#define WRITE_REG 1 /* index of Write cycle timing register */
#define CNTRL_REG 3 /* index of Control register */
@@ -264,7 +252,8 @@ static void opti621_set_pio_mode(ide_drive_t *drive, const u8 pio)

cycle1 = ((first.data_time-1)<<4) | (first.recovery_time-2);
cycle2 = ((second.data_time-1)<<4) | (second.recovery_time-2);
misc = READ_PREFETCH | ((ax-1)<<4) | ((drdy-2)<<1);

misc = ((ax - 1) << 4) | ((drdy - 2) << 1);

#ifdef OPTI621_DEBUG
printk("%s: master: address: %d, data: %d, "

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