Improve warning message on HWP-disabled hybrid processors to state that
intel_pstate requires HWP to be enabled on such processors [1].
Previously it warned that "intel_pstate: CPU model not supported", but
it was misleading.

[1]: https://docs.kernel.org/admin-guide/pm/intel_pstate.html

Signed-off-by: Yohei Kojima <yohei.kojima@sony.com>
---
I tested this patch on my PC equipped with i7-14700. Please note that
you need hybrid processors (i.e. Alder Lake and later) to test this.

After this patch, you will see the improved warning message if you
disable hardware P-state in your BIOS,

$ sudo dmesg -k | grep intel_pstate
[    0.478616] intel_pstate: HWP-disabled hybrid CPU is not supported

whereas this driver works as before if HWP is enabled.

$ sudo dmesg -k | grep intel_pstate
[    0.471387] intel_pstate: HWP enabled by BIOS
[    0.471388] intel_pstate: Intel P-state driver initializing
[    0.472593] intel_pstate: HWP enabled
---
 drivers/cpufreq/intel_pstate.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 11c58af41900..99cac95537b5 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -3823,6 +3823,12 @@ static int __init intel_pstate_init(void)
 		if (no_load)
 			return -ENODEV;
 
+		id = x86_match_cpu(intel_hybrid_scaling_factor);
+		if (id) {
+			pr_info("HWP-disabled hybrid CPU is not supported\n");
+			return -ENODEV;
+		}
+
 		id = x86_match_cpu(intel_pstate_cpu_ids);
 		if (!id) {
 			pr_info("CPU model not supported\n");
-- 
2.43.0

On Fri, May 22, 2026 at 2:14 AM Yohei Kojima <yohei.kojima@sony.com> wrote:
>
> Improve warning message on HWP-disabled hybrid processors to state that
> intel_pstate requires HWP to be enabled on such processors [1].
> Previously it warned that "intel_pstate: CPU model not supported", but
> it was misleading.
>
> [1]: https://docs.kernel.org/admin-guide/pm/intel_pstate.html
>
> Signed-off-by: Yohei Kojima <yohei.kojima@sony.com>
> ---
> I tested this patch on my PC equipped with i7-14700. Please note that
> you need hybrid processors (i.e. Alder Lake and later) to test this.
>
> After this patch, you will see the improved warning message if you
> disable hardware P-state in your BIOS,
>
> $ sudo dmesg -k | grep intel_pstate
> [    0.478616] intel_pstate: HWP-disabled hybrid CPU is not supported
>
> whereas this driver works as before if HWP is enabled.
>
> $ sudo dmesg -k | grep intel_pstate
> [    0.471387] intel_pstate: HWP enabled by BIOS
> [    0.471388] intel_pstate: Intel P-state driver initializing
> [    0.472593] intel_pstate: HWP enabled
> ---
>  drivers/cpufreq/intel_pstate.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 11c58af41900..99cac95537b5 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -3823,6 +3823,12 @@ static int __init intel_pstate_init(void)
>                 if (no_load)
>                         return -ENODEV;
>
> +               id = x86_match_cpu(intel_hybrid_scaling_factor);
> +               if (id) {
> +                       pr_info("HWP-disabled hybrid CPU is not supported\n");
> +                       return -ENODEV;
> +               }
> +
>                 id = x86_match_cpu(intel_pstate_cpu_ids);
>                 if (!id) {
>                         pr_info("CPU model not supported\n");
> --

Applied as 7.2 material, thanks!