[PATCH] Re: 2.6.23-rc2-mm2: sata disk going slow

Hugh Dickins
2007-08-11T22:05:28Z

Why is the G5 so slow with 2.6.23-rc2-mm2? hdparm -t shows 1.8MB/sec
instead of 58MB/sec. alpm-increase-number-of-allowable-device-flags.patch
(raising ATA_DFLAG_CFG_MASK) turns out to be the guilty party: though the
problem doesn't appear until the next patch, which adds ATA_DFLAG_IPM as
the same bit as ATA_DFLAG_PIO. Here's a hotfix against top of -rc2-mm2.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---

include/linux/libata.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- 2.6.23-rc2-mm2/include/linux/libata.h 2007-08-10 12:14:36.000000000 +0100
+++ linux/include/linux/libata.h 2007-08-11 20:21:59.000000000 +0100
@@ -143,9 +143,9 @@ enum {
ATA_DFLAG_IPM = (1 << 8), /* device supports IPM */
ATA_DFLAG_CFG_MASK = (1 << 12) - 1,

- ATA_DFLAG_PIO = (1 << 8), /* device limited to PIO mode */
- ATA_DFLAG_NCQ_OFF = (1 << 9), /* device limited to non-NCQ mode */
- ATA_DFLAG_SPUNDOWN = (1 << 10), /* XXX: for spindown_compat */
+ ATA_DFLAG_PIO = (1 << 12), /* device limited to PIO mode */
+ ATA_DFLAG_NCQ_OFF = (1 << 13), /* device limited to non-NCQ mode */
+ ATA_DFLAG_SPUNDOWN = (1 << 14), /* XXX: for spindown_compat */
ATA_DFLAG_INIT_MASK = (1 << 16) - 1,

ATA_DFLAG_DETACH = (1 << 16),