linux-kernel - Re: [PATCH v2 2/6] Drivers: hv: allow non ACPI compilation for hv_is_hibernation

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Date:   Thu, 2 Feb 2023 06:48:43 -0800
From:   Saurabh Singh Sengar <ssengar@...ux.microsoft.com>
To:     "Michael Kelley (LINUX)" <mikelley@...rosoft.com>
Cc:     "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        Dexuan Cui <decui@...rosoft.com>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        Saurabh Singh Sengar <ssengar@...rosoft.com>
Subject: Re: [PATCH v2 2/6] Drivers: hv: allow non ACPI compilation for
 hv_is_hibernation_supported

On Wed, Feb 01, 2023 at 05:47:44PM +0000, Michael Kelley (LINUX) wrote:
> From: Saurabh Sengar <ssengar@...ux.microsoft.com> Sent: Tuesday, January 31, 2023 10:10 AM
> > 
> > acpi_sleep_state_supported API is only define for CONFIG_ACPI flag and
> > thus it can't be used for non-ACPI builds. Initaly there won't be
> 
> s/Initaly/Initially/

OK

> 
> > hibernate support for non ACPI builds.
> 
> s/hibernate/hibernation/

OK

> 
> > 
> > This change will help adding device tree support in subsequent commits.
> > 
> > Signed-off-by: Saurabh Sengar <ssengar@...ux.microsoft.com>
> > ---
> >  drivers/hv/hv_common.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> > index 52a6f89ccdbd..370ec20d1993 100644
> > --- a/drivers/hv/hv_common.c
> > +++ b/drivers/hv/hv_common.c
> > @@ -234,7 +234,11 @@ EXPORT_SYMBOL_GPL(hv_setup_dma_ops);
> > 
> >  bool hv_is_hibernation_supported(void)
> >  {
> > +#ifdef CONFIG_ACPI
> >  	return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
> > +#else
> > +	return false;
> > +#endif
> 
> Is this patch needed?  If CONFIG_ACPI is not set, then per
> arch/x86/Kconfig, CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT
> is not selected.  In that case, the #ifdef in include/acpi/acpi_bus.h
> provides a stub for acpi_sleep_state_supported() that returns "false".
> So it seems like the existing code should compile and correctly return
> "false" when CONFIG_ACPI is not set.

You are right, if CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT is not set
acpi_sleep_state_supported will return false, but this is applicable only
when CONFIG_ACPI is enable. If CONFIG_ACPI is not enable both these
functions are not defined.

Regards,
Saurabh


> 
> Michael
> 
> >  }
> >  EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
> > 
> > --
> > 2.25.1