Re: [PATCH]AHCI: disable sntf cap for ich8

From: Jeff Garzik
Date: Mon Nov 16 2009 - 22:19:45 EST


On 11/15/2009 08:56 PM, Shaohua Li wrote:
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.

Patch applied.


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.

You work for Intel -- you or somebody needs to research and figure this out... This is an Intel vendor issue that only Intel can definitively resolve.

Jeff


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