Re: [PATCH 08/13] cpufreq: acpi-cpufreq: Take 'dummy' principle one stage further
From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-07-14 16:20:59
Also in:
linux-pm, lkml
On 2020-07-14 17:03, Rafael J. Wysocki wrote:
On Tue, Jul 14, 2020 at 4:51 PM Lee Jones [off-list ref] wrote:quoted
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.Which is kind of ugly in my personal view. I hope that the compiler will actually optimize the extra code away ...quoted
Fixes the following W=1 kernel build warning(s):Well, "Makes the following ... warning(s) go away:" rather ...
Isn't that what we have __maybe_unused and __always_unused for? Robin.
quoted
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 <redacted> Cc: Paul Diefenbaugh <redacted> Cc: Dominik Brodowski <redacted> Cc: Denis Sadykov <redacted> Signed-off-by: Lee Jones <redacted> --- 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_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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