linux-kernel - Re: [PATCH] cpufreq: intel_pstate: Add DMI quirk for Dell Inspiron systems

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Message-ID: <CAJZ5v0h5cLB3X17dLx7-6X4XDkCW2gqRYa_NG-QeRGLv1k0MvA@mail.gmail.com>
Date: Wed, 9 Jul 2025 09:28:09 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: joe.walter@...esensesolutions.com
Cc: srinivas.pandruvada@...ux.intel.com, rafael@...nel.org, 
	viresh.kumar@...aro.org, lenb@...nel.org, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: intel_pstate: Add DMI quirk for Dell Inspiron systems

On Sat, Jun 7, 2025 at 1:42 AM Joe Walter
<joe.walter@...esensesolutions.com> wrote:
>
> Some Dell Inspiron systems experience frequency scaling issues with
> intel_pstate driver where the CPU gets locked at 900MHz after load.
>
> Add DMI quirk table to detect affected Dell Inspiron models and prevent
> intel_pstate from loading, allowing acpi-cpufreq to handle frequency
> scaling instead.
>
> Affected models:
> - Dell Inspiron 15 7000 Gaming
> - Dell Inspiron 7567
> - Dell Inspiron 7559
>
> Tested-by: Joe Walter <joe.walter@...esensesolutions.com>
> Signed-off-by: Joe Walter <joe.walter@...esensesolutions.com>
> ---
>  drivers/cpufreq/intel_pstate.c | 65 ++++++++++++++++++++++------------
>  1 file changed, 42 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 1b1f62ccec92..3aeb04755afa 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -28,7 +28,6 @@
>  #include <linux/pm_qos.h>
>  #include <linux/bitfield.h>
>  #include <trace/events/power.h>
> -#include <linux/dmi.h>
>  #include <linux/units.h>
>
>  #include <asm/cpu.h>
> @@ -48,6 +47,7 @@
>  #ifdef CONFIG_ACPI
>  #include <acpi/processor.h>
>  #include <acpi/cppc_acpi.h>
> +#include <linux/dmi.h>
>  #endif
>
>  #define FRAC_BITS 8
> @@ -299,25 +299,6 @@ struct pstate_funcs {
>
>  static struct pstate_funcs pstate_funcs __read_mostly;
>
> -/* DMI quirk table for systems that should prefer acpi-cpufreq over intel_pstate */
> -static int intel_pstate_prefer_acpi_cpufreq(const struct dmi_system_id *id)
> -{
> -       pr_info("Preferring acpi-cpufreq for %s due to performance issues with intel_pstate\n",
> -               id->ident);
> -       return 1;
> -}
> -
> -static const struct dmi_system_id intel_pstate_acpi_cpufreq_prefer[] = {
> -       {
> -               .callback = intel_pstate_prefer_acpi_cpufreq,
> -               .ident = "Dell Inspiron 15 7000 Gaming",
> -               .matches = {
> -                       DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> -                       DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 15 7000 Gaming"),
> -               },
> -       },
> -       { }
> -};

This isn't a patch against mainline intel_pstate because there are no
DMI checks in there.