From: Tejun Heo <tj@kernel.org>
To: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: Unexpected _GTF length (8)
Date: Sun, 22 Sep 2013 11:59:57 -0400 [thread overview]
Message-ID: <20130922155957.GC28571@htj.dyndns.org> (raw)
In-Reply-To: <CAMeQTsby_CoGq1xAKUEVg_yWyqSSMjfSf6gWWzFRR+-znpPVbw@mail.gmail.com>
On Sun, Sep 22, 2013 at 03:56:35AM +0200, Patrik Jakobsson wrote:
> Where REGS_PER_GTF is defined as 7 which is correct according to ACPI specs.
> Since I'm getting a length of 8 I started digging in the ACPI code and found
> that the length is rounded up to acpi_size (u32 or u64 depending on arch). I
> cannot find any commits that recently touched this though I didn't really dig
> through it all.
It means your bios is buggy.
> I've disassembled the SSDT for the "SataAhci" and everything looks ok. That
> code returns a 56 bit buffer. I also tried calling the _GTF method manually
> which returned the following (padded to 8 bytes by the ACPI code ofc).
>
> {0x10, 0x03, 0x00, 0x00, 0x00, 0xa0, 0xef, 0x00}
>
> Doing a quick google search gives me a few of these _GTF length errors dating
> back to at least 2011. What's going on here? Is this a known error?
Failing to execute _GTF is usally fine to the point where I sometimes
wonder why we bother with it at all. The above command is SET
FEATURES / Enable SATA Feature / DIPM, which enables device side link
powersaving and is a weird thing to do from _GTF anyway as host side
needs configuration too. You can properly configure it using libata
link PM.
Thanks.
--
tejun
next prev parent reply other threads:[~2013-09-22 16:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-22 1:56 Unexpected _GTF length (8) Patrik Jakobsson
2013-09-22 6:25 ` Levente Kurusa
2013-09-22 15:06 ` Patrik Jakobsson
2013-09-22 15:59 ` Tejun Heo [this message]
2013-09-22 17:09 ` Patrik Jakobsson
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