lkml.org 
[lkml]   [2009]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[060/119] [CPUFREQ] Enable ACPI PDC handshake for VIA/Centaur CPUs
    2.6.31-stable review patch.  If anyone has any objections, please let us know.

    ------------------
    From: Harald Welte <HaraldWelte@viatech.com>

    commit d77b81974521c82fa6fda38dfff1b491dcc62a32 upstream.

    In commit 0de51088e6a82bc8413d3ca9e28bbca2788b5b53, we introduced the
    use of acpi-cpufreq on VIA/Centaur CPU's by removing a vendor check for
    VENDOR_INTEL. However, as it turns out, at least the Nano CPU's also
    need the PDC (processor driver capabilities) handshake in order to
    activate the methods required for acpi-cpufreq.

    Since arch_acpi_processor_init_pdc() contains another vendor check for
    Intel, the PDC is not initialized on VIA CPU's. The resulting behavior
    of a current mainline kernel on such systems is: acpi-cpufreq
    loads and it indicates CPU frequency changes. However, the CPU stays at
    a single frequency

    This trivial patch ensures that init_intel_pdc() is called on Intel and
    VIA/Centaur CPU's alike.

    Signed-off-by: Harald Welte <HaraldWelte@viatech.com>
    Signed-off-by: Dave Jones <davej@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    arch/x86/kernel/acpi/processor.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/arch/x86/kernel/acpi/processor.c
    +++ b/arch/x86/kernel/acpi/processor.c
    @@ -79,7 +79,8 @@ void arch_acpi_processor_init_pdc(struct
    struct cpuinfo_x86 *c = &cpu_data(pr->id);

    pr->pdc = NULL;
    - if (c->x86_vendor == X86_VENDOR_INTEL)
    + if (c->x86_vendor == X86_VENDOR_INTEL ||
    + c->x86_vendor == X86_VENDOR_CENTAUR)
    init_intel_pdc(pr, c);

    return;



    \
     
     \ /
      Last update: 2009-12-07 01:33    [W:0.023 / U:95.844 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site