linux-kernel - Re: [PATCH] cpufreq: Remove CPUFREQ

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Date:   Mon, 1 Feb 2021 10:44:15 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>,
        Keguang Zhang <keguang.zhang@...il.com>,
        Kevin Hilman <khilman@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        linux-omap@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH] cpufreq: Remove CPUFREQ_STICKY flag

Viresh,

Am Mon, Feb 01, 2021 at 01:35:51PM +0530 schrieb Viresh Kumar:
> The removal of such a driver is avoided if the driver carries the
> CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
> one should ever need it now. A lot of driver do set this flag, probably
> because they just copied it from another driver.

IIRC, it was required on various ARM systems,[*] as CPUs were registered as
subsys_initcall(), while cpufreq used to be initialized only later, as an
arch_initcall(). If the ordering is opposite now on all architectures (it
wasn't on ARM back then), we should be fine.

[*] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5

Thanks,
	Dominik