linux-kernel - Re: [PATCH v1 2/6] cpufreq: intel_pstate: Do not update global.turbo

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Date: Mon, 3 Jun 2024 20:32:32 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Xi Ruoyao <xry111@...111.site>
Cc: srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>, 
	"Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/6] cpufreq: intel_pstate: Do not update
 global.turbo_disabled after initialization

On Mon, Jun 3, 2024 at 7:44 PM Xi Ruoyao <xry111@...111.site> wrote:
>
> On Mon, 2024-06-03 at 10:11 -0700, srinivas pandruvada wrote:
> > On Mon, 2024-06-03 at 21:12 +0800, Xi Ruoyao wrote:
> > > On Sun, 2024-06-02 at 16:11 -0700, srinivas pandruvada wrote:
> > >
> > > /* snip */
> > >
> > > > What is the output of:
> > > > grep . /sys/devices/system/cpu/intel_pstate/*
> > > >
> > > > Also
> > > > rdmsr 0x771
> > > > rdmsr 0x774
> > > >
> > > >
> > > > Try these three patches. Don't worry about the commit description
> > > > for
> > > > this issue.
> > >
> > > Unfortunately they still do not fix the issue for me.
> > >
> > > The outputs of grep and rdmsr commands are initially:
> > >
> > > /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost:0
> > > /sys/devices/system/cpu/intel_pstate/max_perf_pct:100
> > > /sys/devices/system/cpu/intel_pstate/min_perf_pct:9
> > > /sys/devices/system/cpu/intel_pstate/no_turbo:1
> > > /sys/devices/system/cpu/intel_pstate/num_pstates:41
> > > /sys/devices/system/cpu/intel_pstate/status:active
> > > /sys/devices/system/cpu/intel_pstate/turbo_pct:33
> > > rdmsr 0x771: 10d1f2c
> > > rdmsr 0x774: 1f04
> > >
> > > But it then changes to:
> > >
> > > /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost:0
> > > /sys/devices/system/cpu/intel_pstate/max_perf_pct:100
> > > /sys/devices/system/cpu/intel_pstate/min_perf_pct:9
> > > /sys/devices/system/cpu/intel_pstate/no_turbo:1
> > > /sys/devices/system/cpu/intel_pstate/num_pstates:41
> > > /sys/devices/system/cpu/intel_pstate/status:active
> > > /sys/devices/system/cpu/intel_pstate/turbo_pct:33
> > > rdmsr 0x771: 10c1f2c
> > > rdmsr 0x774: 1f04
> > >
> > > It seems only the output of rdmsr 0x771 has changed.  And if I read
> > > the
> > > SDM correctly it's a "Most_Efficient_Performance" change.
> > That is fine.
> >
> > We don't have any notifications either via ACPI or via HWP interrupt.
> > I think it was working by chance before this change as by the cpufreq
> > core is trying to set policy, the turbo is enabled by the firmware.
> >
> > What is this laptop make and model?
>
> It's a Hasee X5-2021S5H.
>
> Hasee is known for producing some laptops very cheap but often having
> "minor" issues.  So I guess the firmware is doing some stupid thing.
>
> But turbo works just fine on Windows 11 so it'd be better if we could
> make it work for Linux too.

In principle, there are two things that can be done about this.

First, MSR_IA32_MISC_ENABLE_TURBO_DISABLE on this system can be
ignored altogether, but that would require adding a quirk.

Second, a delayed work can be added to check the MSR long enough after
initialization and update global.turbo_disabled if it is 1.  However,
that would require some code surgery.