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From: Tejun Heo <htejun@gmail.com>
To: Jeff Garzik <jeff@garzik.org>
Cc: Arjan van de Ven <arjan@infradead.org>,
	Faik Uygur <faik@pardus.org.tr>,
	Robert Hancock <hancockr@shaw.ca>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: ahci_softreset prevents acpi_power_off
Date: Mon, 15 Jan 2007 22:55:10 +0900	[thread overview]
Message-ID: <45AB87BE.9060304@gmail.com> (raw)
In-Reply-To: <45AB8553.10301@garzik.org>

Jeff Garzik wrote:
> Tejun Heo wrote:
>> Arjan van de Ven wrote:
>>> I'd be interested in finding out how to best test this; if the bios is
>>> really broken I'd love to add a test to the Linux-ready Firmware
>>> Developer Kit for this, so that BIOS developers can make sure future
>>> bioses do not suffer from this bug...
>>
>> As reported, this is almost a butterfly effect.  ->softreset method is
>> only used during initialization and error recovery of ATA devices which
>> has almost nothing to do with the rest of the system.  This is almost
>> like 'changing my mixer input to line-in makes power off fail'.  (it's
>> more related due to ATA ACPI stuff and maybe that's why this happens but
>> I'm trying to make a point here.)
> 
> It's quite possible that the BIOS in question wants AHCI in some
> specific state at poweroff.

I would be surprised if this weren't an accident.  We reset the
controller during initialization, so whether softreset or hardreset is
used, the end status cannot be much different.  And, I really don't
wanna change ahci and/or libata for this.

-- 
tejun

  reply	other threads:[~2007-01-15 13:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.enjQgtLFPdSkeJjKv6eOjULTovQ@ifi.uio.no>
     [not found] ` <fa.1s/e9SHVR6LQC2HgdZRykrqlV5Q@ifi.uio.no>
     [not found]   ` <fa.kpxGqupQMKJxBBFrktFUzuoKc7c@ifi.uio.no>
2007-01-14  1:23     ` Robert Hancock
2007-01-14  3:18       ` Jeff Garzik
2007-01-14 17:50         ` Faik Uygur
2007-01-14 17:59       ` Faik Uygur
2007-01-14 18:06         ` Arjan van de Ven
2007-01-14 18:58           ` Faik Uygur
2007-01-15  4:02           ` Tejun Heo
2007-01-15 13:44             ` Jeff Garzik
2007-01-15 13:55               ` Tejun Heo [this message]
2007-01-11 10:31 Faik Uygur
2007-01-13  1:12 ` Tejun Heo
2007-01-13  5:59   ` Faik Uygur
2007-01-13 12:10   ` Faik Uygur

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