]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[PATCH] libata: use FLUSH_EXT only when driver is larger than LBA28 limit
authorTejun Heo <htejun@gmail.com>
Sat, 11 Nov 2006 11:10:45 +0000 (20:10 +0900)
committerJeff Garzik <jeff@garzik.org>
Sat, 2 Dec 2006 03:45:54 +0000 (22:45 -0500)
commit6fc49adb9417b9c793e8f88d485387bb89ceb733
treed94f536f24e504b1a654c392171fb6f08a195ca2
parent648a88be4a016d2637ace3ae74b85a0512255ee8
[PATCH] libata: use FLUSH_EXT only when driver is larger than LBA28 limit

Many drives support LBA48 even when its capacity is smaller than
1<<28, as LBA48 is required for many functionalities.  FLUSH_EXT is
mandatory for drives w/ LBA48 support.

Interestingly, at least one of such drives (ST960812A) has problems
dealing with FLUSH_EXT.  It eventually completes the command but takes
around 7 seconds to finish in many cases thus drastically slowing down
IO transactions.  This seems to be a firmware bug which sneaked into
production probably because no other ATA driver including linux IDE
issues FLUSH_EXT to drives which report support for LBA48 & FLUSH_EXT
but is smaller than 1<<28 blocks.

This patch adds ATA_DFLAG_FLUSH_EXT which is set iff the drive
supports LBA48 & FLUSH_EXT and is larger than LBA28 limit.  Both cache
flush paths are updated to issue FLUSH_EXT only when the flag is set.
Note that the changed behavior is more inline with the rest of libata.
libata prefers shorter commands whenever possible.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Danny Kukawka <dkukawka@novell.com>
Cc: Stefan Seyfried <seife@novell.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
drivers/ata/libata-core.c
drivers/ata/libata-scsi.c
include/linux/libata.h