ahci: disable SNotification capability for ich8
authorShaohua Li <shaohua.li@intel.com>
Mon, 16 Nov 2009 01:56:05 +0000 (09:56 +0800)
committerMatt Sealey <neko@excel.(none)>
Tue, 10 Aug 2010 16:50:54 +0000 (11:50 -0500)
commitf32cbc21e09e582203dbf426d4d457632eec80cd
treeefa5f3050c01c1f63bece2c2301cb37bb7a3097b
parente5cb3c602d988915108cdb73c65e83745beaad40
ahci: disable SNotification capability for ich8

I obseved there is a sata_async_notification() for every ahci
interrupt. But the async notification does nothing (this is hard
disk drive and no pmp). This cause cpu wastes some time on sntf
register access.

It appears ICH AHCI doesn't support SNotification register, but the
controller reports it does. After quirking it, the async notification
disappears.

PS. it appears all ICH don't support SNotification register from ICH
manual, don't know if we need quirk all ICH. I don't have machines
with all kinds of ICH.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
drivers/ata/ahci.c