Re: [PATCH 1/2] cpupower: fix amd cpu (family < 0x17) active state issue

[Thomas Renninger <trenn@suse.com>]

Hi,

Am Mittwoch, 24. März 2021, 09:28:37 CEST schrieb xufuhai:
> From: xufuhai <xufuhai@kuaishou.com>
> 
> For the old  AMD processor (family < 0x17), cpupower will call the
> amd_pci_get_num_boost_states function, but for the non-root user
> pci_read_byte function (implementation comes from the psutil library),
> val will be set to 0xff, indicating that there is no read function
> callback. At this time, the original logic will set the cpupower turbo
> active state to yes. This is an obvious issue~
> 
> Reproduce procedure:
> 	cpupower frequency-info
> 
> Signed-off-by: xufuhai <xufuhai@kuaishou.com>
> ---
>  tools/power/cpupower/utils/helpers/amd.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/tools/power/cpupower/utils/helpers/amd.c
> b/tools/power/cpupower/utils/helpers/amd.c index 97f2c857048e..6f9504906afa
> 100644
> --- a/tools/power/cpupower/utils/helpers/amd.c
> +++ b/tools/power/cpupower/utils/helpers/amd.c
> @@ -137,6 +137,13 @@ int amd_pci_get_num_boost_states(int *active, int
> *states) return -ENODEV;
> 
>  	val = pci_read_byte(device, 0x15c);
> +
> +	/* If val is 0xff, meaning has no permisson to
> +	 * get the boost states, return -1
> +	 */
> +	if (val == 0xff)
> +		return -1;
> +
There is certainly a cleaner way to do this.., theoretically
pci_read_byte can return 0xff in other cases?

But I guess this is a sufficient way to handle this for now.

Reviewed-by: Thomas Renninger <trenn@suse.de>

Thanks,

        Thomas