On 2020-07-14 17:03, Rafael J. Wysocki wrote:
On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <[email protected]> wrote:
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 ...
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.
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 <[email protected]>
Cc: Paul Diefenbaugh <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: Denis Sadykov <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
---
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
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