Re: [PATCH 1/3] intel_pstate: skip the driver if Sun server has ACPI _PPC method

[ethan zhao]

Dirk,

On 2014/11/21 0:50, Dirk Brandewie wrote:
> On 11/19/2014 12:22 PM, Linda Knippers wrote:
> > On 11/18/2014 3:37 AM, Ethan Zhao wrote:
> > > Oracle Sun X86 servers have dynamic power capping capability that 
> > > works via
> > > ACPI _PPC method etc, so skip loading this driver if Sun server has 
> > > ACPI _PPC
> > > enabled.
> > >
> > > Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> > > ---
> > >   drivers/cpufreq/intel_pstate.c | 20 ++++++++++++++++++++
> > >   1 file changed, 20 insertions(+)
> > >
> > > diff --git a/drivers/cpufreq/intel_pstate.c 
> > > b/drivers/cpufreq/intel_pstate.c
> > > index 27bb6d3..5498eb0 100644
> > > --- a/drivers/cpufreq/intel_pstate.c
> > > +++ b/drivers/cpufreq/intel_pstate.c
> > > @@ -943,6 +943,21 @@ static bool intel_pstate_no_acpi_pss(void)
> > >       return true;
> > >   }
> > >
> > > +static bool intel_pstate_has_acpi_ppc(void)
> > > +{
> > > +    int i;
> > > +
> > > +    for_each_possible_cpu(i) {
> > > +        struct acpi_processor *pr = per_cpu(processors, i);
> > > +
> > > +        if (!pr)
> > > +            continue;
> > > +        if (acpi_has_method(pr->handle, "_PPC"))
> > > +            return true;
> > > +    }
> > > +    return false;
> > > +}
> > > +
> > >   struct hw_vendor_info {
> > >       u16  valid;
> > >       char oem_id[ACPI_OEM_ID_SIZE];
> > > @@ -952,6 +967,7 @@ struct hw_vendor_info {
> > >   /* Hardware vendor-specific info that has its own power management 
> > > modes */
> > >   static struct hw_vendor_info vendor_info[] = {
> > >       {1, "HP    ", "ProLiant"},
> > > +    {1, "ORACLE", ""},
> > >       {0, "", ""},
> > >   };
> > >
> > > @@ -969,12 +985,16 @@ static bool 
> > > intel_pstate_platform_pwr_mgmt_exists(void)
> > >               !strncmp(hdr.oem_table_id, v_info->oem_table_id, 
> > > ACPI_OEM_TABLE_ID_SIZE) &&
> > >               intel_pstate_no_acpi_pss())
> > >               return true;
> > > +        if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE) &&
> > > +            intel_pstate_has_acpi_ppc())
> >
> > We need try this on a few platforms to make sure this patch doesn't 
> > break the
> > HP platforms that may or may not need this driver, depending on the 
> > BIOS settings.
>
> It looks like HP systems would get swept up in this check too if they 
> have _PPC
   No , this patch checks the oem_id against 'ORACLE" first, will not 
affect other vendors
  even they have _PPC.

> What about extending the hw_vendor_info struct to include whether _PSS or
 Except refer to ACPI DSDT, I don't know how to fill such info.
> _PPC should be done for the platform since it appears that oracle and HP
> have implemented similar functionality using two different methods.
  Maybe Linda could answer this whether HP also has _PPC and should be 
wept out.
  But that doesn't happen with on the same box at the same time.

  Thanks,
  Ethan
> > I don't suppose you tested on a ProLiant too?
> >
> > -- ljk
> >
> > > +            return true;
> > >       }
> > >
> > >       return false;
> > >   }
> > >   #else /* CONFIG_ACPI not enabled */
> > >   static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { 
> > > return false; }
> > > +static inline bool intel_pstate_has_acpi_ppc(void) { return false; }
> > >   #endif /* CONFIG_ACPI */
> > >
> > >   static int __init intel_pstate_init(void)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/