From: Jeff Garzik <jeff@garzik.org>
To: Tejun Heo <tj@kernel.org>
Cc: IDE/ATA development list <linux-ide@vger.kernel.org>,
"Zhao, Richard" <Richard.Zhao@amd.com>,
shane.huang@amd.com
Subject: Re: [PATCH RFC] ahci: implement handoff quirk
Date: Sat, 11 Apr 2009 14:02:06 -0400 [thread overview]
Message-ID: <49E0DB1E.8070701@garzik.org> (raw)
In-Reply-To: <49E0D8B7.8010206@kernel.org>
Tejun Heo wrote:
> Jeff Garzik wrote:
>> We probably need to do this...
>>
>> it's not a controller requirement but a BIOS one, so in theory even an
>> existing, deployed AHCI 1.2 platform could suddenly require BIOS/OS
>> handoff, if a BIOS update suddenly starts doing new and weird stuff in SMI.
>>
>> Note that we need to do BIOS/OS handoff upon resume as well as at boot
>> time.
>
> Yeah, probably. Do you know of any system which makes use of this
> feature? I'm a bit uneasy about committing it without any testing.
I don't.
But the purpose of the feature is to tell BIOS to cleanup and stop using
the hardware. It's a dumb feature, because of compatibility realities,
but hey, other network and SCSI drivers have been doing this sort of
synchronization with their on-board firmwares for years.
IMO the more dangerous route is to continue loading ahci, without first
telling the BIOS to clean up and get out of our way.
Jeff
next prev parent reply other threads:[~2009-04-11 18:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-18 3:37 [PATCH RFC] ahci: implement handoff quirk Tejun Heo
2009-04-11 16:54 ` Jeff Garzik
2009-04-11 17:51 ` Tejun Heo
2009-04-11 18:02 ` Jeff Garzik [this message]
2009-04-14 9:16 ` Tejun Heo
2009-04-14 9:41 ` Jeff Garzik
2009-04-15 1:54 ` Huang, Shane
2009-12-17 6:34 ` Jeff Garzik
2009-12-18 3:54 ` Robert Hancock
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