From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Len Brown <lenb@kernel.org>
Cc: Philip Langdale <philipl@overt.org>,
Jeff Garrett <jeff@jgarrett.org>,
Andi Kleen <andi@firstfloor.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-acpi@vger.kernel.org, luming.yu@intel.com,
venki@google.com
Subject: Re: acpi_idle: Very idle Core i7 machine never enters C3
Date: Tue, 25 May 2010 13:37:01 +0100 [thread overview]
Message-ID: <20100525123701.GA7876@srcf.ucam.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1005250125590.20648@localhost.localdomain>
On Tue, May 25, 2010 at 01:43:26AM -0400, Len Brown wrote:
> I'm told by the hardware guys that BM_STS is _not_ always
> a NOP, and so we're not supposed to simply ignore it on C3 --
> though it should be extremely rare that we see it set.
> If it is ever set, it should go on and off depending on
> activity on some latency sensitive device, like out on the LPC.
> It may be possible for the BIOS writer to configure the chipset
> so that BM_STS is enabled always, presumably to accomodate
> some latency sensitve device -- or maybe by mistake.
On some hardware we've seen BM_STS be enabled approximately 50% of the
time without any obvious cause.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2010-05-25 12:37 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-26 8:47 acpi_idle: Very idle Core i7 machine never enters C3 Jeff Garrett
2010-01-26 12:41 ` peng huang
2010-01-26 14:59 ` Jeff Garrett
2010-01-27 13:27 ` peng huang
2010-02-05 16:22 ` Jeff Garrett
2010-01-26 21:45 ` Andi Kleen
2010-02-05 16:09 ` Jeff Garrett
2010-02-05 17:45 ` Len Brown
2010-02-05 20:53 ` Jeff Garrett
2010-04-27 2:40 ` Philip Langdale
2010-04-27 7:26 ` Len Brown
2010-04-27 15:41 ` Philip Langdale
2010-04-27 12:47 ` Jeff Garrett
2010-04-30 14:57 ` Philip Langdale
2010-04-30 16:25 ` Len Brown
2010-04-30 17:44 ` Matthew Garrett
2010-04-30 18:35 ` Philip Langdale
2010-05-25 5:43 ` Len Brown
2010-05-25 5:59 ` Yu, Luming
2010-05-25 12:39 ` Matthew Garrett
2010-05-25 12:43 ` Matthew Garrett
2010-05-25 15:33 ` Len Brown
2010-05-25 18:55 ` Matthew Garrett
2010-07-21 21:31 ` [PATCH] ACPI: make acpi_idle Nehalem-aware Len Brown
2010-07-22 0:53 ` Venkatesh Pallipadi
2010-07-22 7:47 ` Andi Kleen
2010-07-22 15:57 ` Len Brown
2010-07-22 21:21 ` [PATCH] ACPI: skip checking BM_STS if the BIOS doesn't ask for it Len Brown
2010-07-22 21:40 ` [PATCH] ACPI: create "processor.bm_check_disable" boot param Len Brown
2010-07-26 7:24 ` Andi Kleen
2010-07-27 0:19 ` Len Brown
2010-07-27 11:28 ` Andi Kleen
2010-07-28 18:58 ` Len Brown
2010-07-22 21:25 ` [PATCH] ACPI: make acpi_idle Nehalem-aware Iain
2010-07-22 21:53 ` Iain
2010-07-22 22:01 ` Len Brown
2010-07-23 12:40 ` Iain
2010-08-03 6:55 ` Pavel Machek
2010-08-03 7:05 ` Andi Kleen
2010-05-25 12:37 ` Matthew Garrett [this message]
2010-05-25 15:40 ` acpi_idle: Very idle Core i7 machine never enters C3 Len Brown
2010-07-22 5:34 ` Len Brown
2010-02-01 14:10 ` Pavel Machek
2010-02-05 16:30 ` Jeff Garrett
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