linux-kernel - Re: [PATCH 2/2] cpufreq: CPPC: Fix error handling in cppc_scale_freq

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Message-ID: <baef79be-5969-fa4b-3802-ac49d071b11b@hisilicon.com>
Date: Thu, 31 Jul 2025 12:21:01 +0800
From: Jie Zhan <zhanjie9@...ilicon.com>
To: Markus Elfring <Markus.Elfring@....de>, <linux-pm@...r.kernel.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>, Viresh Kumar
	<viresh.kumar@...aro.org>
CC: LKML <linux-kernel@...r.kernel.org>, <linuxarm@...wei.com>, Beata
 Michalska <beata.michalska@....com>, Bowen Yu <yubowen8@...wei.com>, Huisong
 Li <lihuisong@...wei.com>, Ionela Voinescu <ionela.voinescu@....com>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>, Lifeng Zheng
	<zhenglifeng1@...wei.com>, Prashant Malani <pmalani@...gle.com>
Subject: Re: [PATCH 2/2] cpufreq: CPPC: Fix error handling in
 cppc_scale_freq_workfn()



On 31/07/2025 02:38, Markus Elfring wrote:
>> Perf counters could be 0 if the cpu is in a low-power idle state. Just try
>> it again next time and update the frequency scale when the cpu is active
>> and perf counters successfully return.
>>
>> Also, remove the FIE source on an actual failure.
> 
> How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16#n145
> 
> Regards,
> Markus

Hi Markus,

We don't think it's necessarily a bugfix that should be backported to
old/stable kernels.  This is mainly an extra error handling for cases that
may happen on our platform when a CPU is in a deep idle state.

Similar patches were merged before.
https://lore.kernel.org/linux-pm/20240929033214.1039485-2-zhanjie9@hisilicon.com/

Perhaps the 'Fix' in the patch title is a bit misleading.  I'll write a
more appropriate patch description in the following version.

Thanks,
Jie