Messages in this thread | | | Subject | Re: [PATCH AUTOSEL 4.19 123/158] cpufreq: Don't skip frequency validation for has_target() drivers | From | "Rafael J. Wysocki" <> | Date | Tue, 16 Jul 2019 11:21:34 +0200 |
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On 7/15/2019 4:17 PM, Sasha Levin wrote: > From: Viresh Kumar <viresh.kumar@linaro.org> > > [ Upstream commit 9801522840cc1073f8064b4c979b7b6995c74bca ] > > CPUFREQ_CONST_LOOPS was introduced in a very old commit from pre-2.6 > kernel release by commit 6a4a93f9c0d5 ("[CPUFREQ] Fix 'out of sync' > issue"). > > Basically, that commit does two things: > > - It adds the frequency verification code (which is quite similar to > what we have today as well). > > - And it sets the CPUFREQ_CONST_LOOPS flag only for setpolicy drivers, > rightly so based on the code we had then. The idea was to avoid > frequency validation for setpolicy drivers as the cpufreq core doesn't > know what frequency the hardware is running at and so no point in > doing frequency verification. > > The problem happened when we started to use the same CPUFREQ_CONST_LOOPS > flag for constant loops-per-jiffy thing as well and many has_target() > drivers started using the same flag and unknowingly skipped the > verification of frequency. There is no logical reason behind skipping > frequency validation because of the presence of CPUFREQ_CONST_LOOPS > flag otherwise. > > Fix this issue by skipping frequency validation only for setpolicy > drivers and always doing it for has_target() drivers irrespective of > the presence or absence of CPUFREQ_CONST_LOOPS flag. > > cpufreq_notify_transition() is only called for has_target() type driver > and not for set_policy type, and the check is simply redundant. Remove > it as well. > > Also remove () around freq comparison statement as they aren't required > and checkpatch also warns for them. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > drivers/cpufreq/cpufreq.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index d3213594d1a7..80942ec34efd 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -321,12 +321,10 @@ static void cpufreq_notify_transition(struct cpufreq_policy *policy, > * which is not equal to what the cpufreq core thinks is > * "old frequency". > */ > - if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { > - if (policy->cur && (policy->cur != freqs->old)) { > - pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n", > - freqs->old, policy->cur); > - freqs->old = policy->cur; > - } > + if (policy->cur && policy->cur != freqs->old) { > + pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n", > + freqs->old, policy->cur); > + freqs->old = policy->cur; > } > > for_each_cpu(freqs->cpu, policy->cpus) { > @@ -1543,8 +1541,7 @@ static unsigned int __cpufreq_get(struct cpufreq_policy *policy) > if (policy->fast_switch_enabled) > return ret_freq; > > - if (ret_freq && policy->cur && > - !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { > + if (has_target() && ret_freq && policy->cur) { > /* verify no discrepancy between actual and > saved value exists */ > if (unlikely(ret_freq != policy->cur)) {
This is not -stable material, please drop it.
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