linux-kernel - [PATCH 08/13] cpufreq: acpi-cpufreq: Take 'dummy' principle one stage further

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Date:   Tue, 14 Jul 2020 15:50:44 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     rjw@...ysocki.net, viresh.kumar@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
        Andy Grover <andrew.grover@...el.com>,
        Paul Diefenbaugh <paul.s.diefenbaugh@...el.com>,
        Dominik Brodowski <linux@...do.de>,
        Denis Sadykov <denis.m.sadykov@...el.com>
Subject: [PATCH 08/13] cpufreq: acpi-cpufreq: Take 'dummy' principle one stage further

If we fail to use a variable, even a 'dummy' one, then the compiler
complains that it is set but not used.  We know this is fine, so we
set it to its own value here.

Fixes the following W=1 kernel build warning(s):

 drivers/cpufreq/acpi-cpufreq.c: In function ‘cpu_freq_read_intel’:
 drivers/cpufreq/acpi-cpufreq.c:247:11: warning: variable ‘dummy’ set but not used [-Wunused-but-set-variable]
 drivers/cpufreq/acpi-cpufreq.c: In function ‘cpu_freq_read_amd’:
 drivers/cpufreq/acpi-cpufreq.c:265:11: warning: variable ‘dummy’ set but not used [-Wunused-but-set-variable]

Cc: Andy Grover <andrew.grover@...el.com>
Cc: Paul Diefenbaugh <paul.s.diefenbaugh@...el.com>
Cc: Dominik Brodowski <linux@...do.de>
Cc: Denis Sadykov <denis.m.sadykov@...el.com>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/cpufreq/acpi-cpufreq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 429e5a36c08a9..d38a693b48e03 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -247,6 +247,7 @@ static u32 cpu_freq_read_intel(struct acpi_pct_register *not_used)
 	u32 val, dummy;
 
 	rdmsr(MSR_IA32_PERF_CTL, val, dummy);
+	dummy &= dummy; /* Silence set but not used warning */
 	return val;
 }
 
@@ -264,6 +265,7 @@ static u32 cpu_freq_read_amd(struct acpi_pct_register *not_used)
 	u32 val, dummy;
 
 	rdmsr(MSR_AMD_PERF_CTL, val, dummy);
+	dummy &= dummy; /* Silence set but not used warning */
 	return val;
 }
 
-- 
2.25.1