RE: [PATCH] ACPI: bus: Fix osc_sb_cppc_not_supported check

[Yuan, Perry]

[AMD Official Use Only - General]

Hi Rafael:

> -----Original Message-----
> From: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> Sent: Saturday, June 25, 2022 12:12 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>
> Cc: Huang, Ray <Ray.Huang@xxxxxxx>; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; Rafael J. Wysocki <rafael@xxxxxxxxxx>; Len
> Brown <lenb@xxxxxxxxxx>; Mika Westerberg
> <mika.westerberg@xxxxxxxxxxxxxxx>; ACPI Devel Maling List <linux-
> acpi@xxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>;
> Fontenot, Nathan <Nathan.Fontenot@xxxxxxx>; Su, Jinzhou (Joe)
> <Jinzhou.Su@xxxxxxx>; Huang, Shimmer <Xinmei.Huang@xxxxxxx>; Du,
> Xiaojian <Xiaojian.Du@xxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx>;
> Linux PM <linux-pm@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH] ACPI: bus: Fix osc_sb_cppc_not_supported check
> 
> [CAUTION: External Email]
> 
> On Fri, Jun 24, 2022 at 2:00 PM Perry Yuan <Perry.Yuan@xxxxxxx> wrote:
> >
> > The patch fixs the osc_sb_cppc_not_supported variable checking
> > Otherwise the cppc acpi driver will be failed to register causing AMD
> > pstate driver failed to load when calling acpi_cpc_valid()
> >
> > Fixes: c42fa24b447("ACPI: bus: Avoid using CPPC if not supported by
> > firmware")
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > ---
> >  drivers/acpi/bus.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index
> > 4d7c51a33b01..9731e4a1e338 100644
> > --- a/drivers/acpi/bus.c
> > +++ b/drivers/acpi/bus.c
> > @@ -359,7 +359,7 @@ static void
> acpi_bus_osc_negotiate_platform_control(void)
> >         }
> >
> >  #ifdef CONFIG_ACPI_CPPC_LIB
> > -       osc_sb_cppc_not_supported = !(capbuf_ret[OSC_SUPPORT_DWORD] &
> > +       osc_sb_cppc_not_supported = !(capbuf_ret[OSC_SUPPORT_DWORD] &&
> >                         (OSC_SB_CPC_SUPPORT | OSC_SB_CPCV2_SUPPORT));
> 
> This certainly is not a correct fix, because it causes osc_sb_cppc_not_supported
> to always be true if capbuf_ret[OSC_SUPPORT_DWORD] is not zero.
> 
> >  #endif

That is true, I will send another fix solution soon.

Perry  

> >
> > --
> > 2.25.1
> >