Re: [PATCH] powerpc/pseries: energy driver only print message when LPAR guest

[Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>]

* Nicholas Piggin <npiggin@gmail.com> [2017-07-21 11:16:44]:

> On Thu, 20 Jul 2017 23:03:21 +1000
> Michael Ellerman <mpe@ellerman.id.au> wrote:
> 
> > Nicholas Piggin <npiggin@gmail.com> writes:
> > 
> > > This driver currently reports the H_BEST_ENERGY is unsupported even
> > > when booting in a non-LPAR environment (e.g., powernv). Prevent it.  
> > 
> > Just delete the printk(). Users don't know what that means, and
> > developers have other better ways to detect that the hcall is missing if
> > anyone cares.
> > 
> > cheers
> 
> powerpc/pseries: energy driver do not print failure message
> 
> This driver currently reports the H_BEST_ENERGY is unsupported (even
> when booting in a non-LPAR environment). This is not something the
> administrator can do much with, and not significant for debugging.
> 
> Remove it.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>


> ---
>  arch/powerpc/platforms/pseries/pseries_energy.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
> index 164a13d3998a..35c891aabef0 100644
> --- a/arch/powerpc/platforms/pseries/pseries_energy.c
> +++ b/arch/powerpc/platforms/pseries/pseries_energy.c
> @@ -229,10 +229,9 @@ static int __init pseries_energy_init(void)
>  	int cpu, err;
>  	struct device *cpu_dev;
> 
> -	if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY)) {
> -		printk(KERN_INFO "Hypercall H_BEST_ENERGY not supported\n");
> -		return 0;
> -	}
> +	if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
> +		return 0; /* H_BEST_ENERGY hcall not supported */
> +

The first patch (!firmware_has_feature(FW_FEATURE_LPAR)) would be
ideal, but we do not have this in KVM guest case also. Hence I take
mpe's suggestion.  Removing the print is fine.

--Vaidy