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

[Hugh Dickins]

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@xxxxxxxxxxx>
---

 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),
-
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