Re: [PATCH 3/3] cpufreq/amd-pstate: Remove warning for X86_FEATURE_CPPC on Zen1 and Zen2

[Xiaojian Du <xiaojidu@amd.com>]

Hi Gautham,

On 2024/8/13 17:54, Gautham R. Shenoy wrote:
> ...
>
> This feature bit corresponds to CPUID 0x80000008.ebx[27] which is a
> reserved bit on the Zen1 and Zen2 platforms, and is expected to be
> cleared on these platforms. Thus printing the warning message for Zen1
> and Zen2 models when X86_FEATURE_CPPC is incorrect. Fix this.
>
> ...
>   	if (!cpu_feature_enabled(X86_FEATURE_CPPC)) {
> -		if (cpu_feature_enabled(X86_FEATURE_ZEN1) || cpu_feature_enabled(X86_FEATURE_ZEN2)) {
> -			if (c->x86_model > 0x60 && c->x86_model < 0xaf)
> -				warn = true;

Some models of ZEN2 APU/CPU require this warning info, like Renoir 
(Ryzen 7 4800H mobile APU/4750G desktop APU,
Ryzen 5 4600 desktop CPU), Lucienne (Ryzen 5 5500U mobile APU) and 
Aerith (APU of Steam Deck console).

So it has to use model ID to narrow down the coverage.

For ZEN1 APU/CPU, this warning can be removed completely, because ZEN1 
doesn't support CPPC.

Thanks,
Xiaojian

> -		} else if (cpu_feature_enabled(X86_FEATURE_ZEN3) || cpu_feature_enabled(X86_FEATURE_ZEN4)) {
> +		if (cpu_feature_enabled(X86_FEATURE_ZEN3) ||
> +		    cpu_feature_enabled(X86_FEATURE_ZEN4)) {
>   			if ((c->x86_model > 0x10 && c->x86_model < 0x1F) ||
>   					(c->x86_model > 0x40 && c->x86_model < 0xaf))
>   				warn = true;