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

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Date: Mon, 03 Jun 2024 21:10:36 -0700
From: srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, Xi Ruoyao <xry111@...111.site>
Cc: "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, 2024-06-03 at 11:47 -0700, srinivas pandruvada wrote:
> On Mon, 2024-06-03 at 20:32 +0200, Rafael J. Wysocki wrote:
> > 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.
> 
Try the attached diff for this case.

Thanks,
Srinivas

> I was about to send this suggestion.
> 
> For the first one we can always program the HWP_REQ.max to
> HWP_CAP.max
> and  let hardware do the clipping. But this is not friendly to
> passive
> mode. But display of scalig_max_freq still should reflect the
> reality.
> 
> 
> Thanks,
> Srinivas
> 
> > 
> 
> 


View attachment "delayed_turbo_check.diff" of type "text/x-patch" (1067 bytes)