Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Tue, 14 Jul 2020 19:43:48 +0200 | Subject | Re: [PATCH 10/13] cpufreq: powernow-k8: Make use of known set but not used variables |
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On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <lee.jones@linaro.org> 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. > > Fixes the following W=1 kernel build warning(s): > > drivers/cpufreq/powernow-k8.c: In function ‘pending_bit_stuck’: > drivers/cpufreq/powernow-k8.c:89:10: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable] > 89 | u32 lo, hi; > | ^~ > drivers/cpufreq/powernow-k8.c: In function ‘core_voltage_pre_transition’: > drivers/cpufreq/powernow-k8.c:285:14: warning: variable ‘lo’ set but not used [-Wunused-but-set-variable] > 285 | u32 maxvid, lo, rvomult = 1; > | ^~ > > Cc: Andreas Herrmann <herrmann.der.user@googlemail.com> > Cc: Dominik Brodowski <linux@brodo.de> > Cc: Pavel Machek <pavel@ucw.cz> > Cc: Paul Devriendt <paul.devriendt@amd.com> > Cc: Mark Langsdorf <mark.langsdorf@amd.com> > Signed-off-by: Lee Jones <lee.jones@linaro.org> > --- > drivers/cpufreq/powernow-k8.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c > index 3984959eed1d5..b76df81044c4f 100644 > --- a/drivers/cpufreq/powernow-k8.c > +++ b/drivers/cpufreq/powernow-k8.c > @@ -89,6 +89,7 @@ static int pending_bit_stuck(void) > u32 lo, hi; > > rdmsr(MSR_FIDVID_STATUS, lo, hi); > + hi &= hi; /* Silence set but not used warning */
Hmm.
What about using __always_unused for this?
> return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0; > } > > @@ -292,6 +293,7 @@ static int core_voltage_pre_transition(struct powernow_k8_data *data, > rvomult = 2; > rvosteps *= rvomult; > rdmsr(MSR_FIDVID_STATUS, lo, maxvid); > + lo &= lo; /* Silence set but not used warning */ > maxvid = 0x1f & (maxvid >> 16); > pr_debug("ph1 maxvid=0x%x\n", maxvid); > if (reqvid < maxvid) /* lower numbers are higher voltages */ > -- > 2.25.1 >
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