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From: Kevin Locke <kevin@kevinlocke.name>
To: Petr Pavlu <petr.pavlu@suse.com>
Cc: rafael@kernel.org, lenb@kernel.org, viresh.kumar@linaro.org,
	pmladek@suse.com, mcgrof@kernel.org, linux-acpi@vger.kernel.org,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] ACPI: cpufreq: use a platform device to load ACPI PPC and PCC drivers
Date: Tue, 9 May 2023 18:00:07 -0600	[thread overview]
Message-ID: <ZFreh8SDMX67EaB6@kevinlocke.name> (raw)
In-Reply-To: <20230316151036.10181-1-petr.pavlu@suse.com>

On Thu, 2023-03-16 at 16:10 +0100, Petr Pavlu wrote:
> The patch extends the ACPI parsing logic to check the ACPI namespace if
> the PPC or PCC interface is present and creates a virtual platform
> device for each if it is available. The acpi-cpufreq and pcc-cpufreq
> drivers are then updated to map to these devices.
> 
> This allows to try loading acpi-cpufreq and pcc-cpufreq only once during
> boot and only if a given interface is available in the firmware.

As a result of this patch (691a637123470bfe63bccf5836ead40fac4c7fab)
my ThinkPad T430 with an i5-3320M CPU configured with
CONFIG_X86_INTEL_PSTATE=y and CONFIG_X86_ACPI_CPUFREQ=m (Debian's
amd64 kernel config) now logs

kernel: acpi-cpufreq: probe of acpi-cpufreq failed with error -17

during boot.  Presumably this occurs because loading acpi-cpufreq
returns -EEXIST when intel-pstate is already loaded (or built-in, as
in this case).  I'm unsure why the message was not printed before;
perhaps a difference between driver probing for platform and cpu bus
types?  Although the error message is not wrong, it may lead to
unnecessary investigation by sysadmins, as it did for me.  I thought
it was worth reporting so you can consider whether the change is
desirable.

Cheers,
Kevin

  parent reply	other threads:[~2023-05-10  0:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16 15:10 [PATCH v4] ACPI: cpufreq: use a platform device to load ACPI PPC and PCC drivers Petr Pavlu
2023-03-20 17:55 ` Rafael J. Wysocki
2023-05-10  0:00 ` Kevin Locke [this message]
2023-05-10  8:48   ` Petr Pavlu
2023-05-10 12:21     ` Rafael J. Wysocki

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