From: Len Brown <lenb@kernel.org>
To: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: linux-acpi@vger.kernel.org, Jens Axboe <jens.axboe@oracle.com>,
Chris Mason <chris.mason@oracle.com>
Subject: Re: [PATCH] Enable bit 11 in _PDC to advertise hw coord
Date: Fri, 06 Feb 2009 23:10:03 -0500 (EST) [thread overview]
Message-ID: <alpine.LFD.2.00.0902062309560.26256@localhost.localdomain> (raw)
In-Reply-To: <20090202195717.GA24510@linux-os.sc.intel.com>
applied
thanks,
--
Len Brown, Intel Open Source Technology Center
On Mon, 2 Feb 2009, Pallipadi, Venkatesh wrote:
>
> Bit 11 in intel PDC definitions is meant for OS capability to handle
> hardware coordination of P-states. In Linux we have always supported
> hwardware coordination of P-states. Just let the BIOSes know that we
> support it, by setting this bit.
>
> Some BIOSes use this bit to choose between hardware or software coordination
> and without this change below, BIOSes switch to software coordination, which
> is not very optimal in terms of power consumption and extra wakeups from idle.
>
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
>
> ---
> include/acpi/pdc_intel.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> Index: linux-2.6/include/acpi/pdc_intel.h
> ===================================================================
> --- linux-2.6.orig/include/acpi/pdc_intel.h 2009-01-20 16:11:20.000000000 -0800
> +++ linux-2.6/include/acpi/pdc_intel.h 2009-02-02 10:32:06.000000000 -0800
> @@ -14,6 +14,7 @@
> #define ACPI_PDC_SMP_T_SWCOORD (0x0080)
> #define ACPI_PDC_C_C1_FFH (0x0100)
> #define ACPI_PDC_C_C2C3_FFH (0x0200)
> +#define ACPI_PDC_SMP_P_HWCOORD (0x0800)
>
> #define ACPI_PDC_EST_CAPABILITY_SMP (ACPI_PDC_SMP_C1PT | \
> ACPI_PDC_C_C1_HALT | \
> @@ -22,6 +23,7 @@
> #define ACPI_PDC_EST_CAPABILITY_SWSMP (ACPI_PDC_SMP_C1PT | \
> ACPI_PDC_C_C1_HALT | \
> ACPI_PDC_SMP_P_SWCOORD | \
> + ACPI_PDC_SMP_P_HWCOORD | \
> ACPI_PDC_P_FFH)
>
> #define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \
> --
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>
prev parent reply other threads:[~2009-02-07 4:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-02 19:57 [PATCH] Enable bit 11 in _PDC to advertise hw coord Pallipadi, Venkatesh
2009-02-04 8:57 ` Jens Axboe
2009-02-04 19:53 ` Henrique de Moraes Holschuh
2009-02-04 20:06 ` Pallipadi, Venkatesh
2009-02-04 20:40 ` Greg KH
2009-02-08 19:51 ` [stable] " Greg KH
2009-02-07 4:10 ` Len Brown [this message]
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