Messages in this thread | | | From | "Yuan, Perry" <> | Subject | RE: [PATCH v3 8/8] cpufreq: amd_pstate: add driver working mode status sysfs entry | Date | Sun, 13 Nov 2022 16:18:23 +0000 |
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[AMD Official Use Only - General]
Hi Mario.
> -----Original Message----- > From: Limonciello, Mario <Mario.Limonciello@amd.com> > Sent: Tuesday, November 8, 2022 2:10 AM > To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; Huang, > Ray <Ray.Huang@amd.com>; viresh.kumar@linaro.org > Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan > <Nathan.Fontenot@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; Huang, Shimmer > <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng, > Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v3 8/8] cpufreq: amd_pstate: add driver working mode > status sysfs entry > > On 11/7/2022 11:57, Perry Yuan wrote: > > While amd-pstate driver was loaded with specific driver mode, it will > > need to check which mode is enabled for the pstate driver,add this > > sysfs entry to show the current status > > > > $ cat /sys/devices/system/cpu/amd-pstate/status > > active > > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> > > --- > > drivers/cpufreq/amd-pstate.c | 44 > > ++++++++++++++++++++++++++++++++++++ > > You should update the matching amd-pstate documentation for this new > sysfs file. > > > 1 file changed, 44 insertions(+) > > > > diff --git a/drivers/cpufreq/amd-pstate.c > > b/drivers/cpufreq/amd-pstate.c index 6958c5fd9e1c..eadcc9d61d39 > 100644 > > --- a/drivers/cpufreq/amd-pstate.c > > +++ b/drivers/cpufreq/amd-pstate.c > > @@ -65,6 +65,8 @@ static int disable_pstate_load __initdata; > > static int epp_off __initdata; > > > > static struct cpufreq_driver *default_pstate_driver; > > +static struct cpufreq_driver amd_pstate_epp_driver; static struct > > +cpufreq_driver amd_pstate_driver; > > static struct amd_cpudata **all_cpu_data; > > > > static struct amd_pstate_params global_params; @@ -819,6 +821,46 @@ > > static ssize_t store_pstate_dynamic_boost(struct kobject *a, > > return count; > > } > > > > +static ssize_t amd_pstate_show_status(char *buf) { > > + if (!default_pstate_driver) > > + return sprintf(buf, "off\n"); > > + > > + return sprintf(buf, "%s\n", default_pstate_driver == > &amd_pstate_epp_driver ? > > + "active" : "passive"); > > +} > > + > > +static int amd_pstate_update_status(const char *buf, size_t size) { > > + /* FIXME: add driver dynamic switching code */ > > + return 0; > > +} > > So "Effectively" this is read only right now. I think it's better to mark the sysfs > file as read only and not bother to populate "store" > callback until you're ready to allow dynamically swapping back and forth. > > If you want to keep the code there, then I think you should return an - > EOPNOTSUPP error code for amd_pstate_update_status.
Yes, changed to return EOPNOTSUPP code in V4. Please help to take a look. Thanks .
Perry.
> > > + > > +static ssize_t show_status(struct kobject *kobj, > > + struct kobj_attribute *attr, char *buf) { > > + ssize_t ret; > > + > > + mutex_lock(&amd_pstate_driver_lock); > > + ret = amd_pstate_show_status(buf); > > + mutex_unlock(&amd_pstate_driver_lock); > > + > > + return ret; > > +} > > + > > +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b, > > + const char *buf, size_t count) { > > + char *p = memchr(buf, '\n', count); > > + int ret; > > + > > + mutex_lock(&amd_pstate_driver_lock); > > + ret = amd_pstate_update_status(buf, p ? p - buf : count); > > + mutex_unlock(&amd_pstate_driver_lock); > > + > > + return ret < 0 ? ret : count; > > +} > > + > > cpufreq_freq_attr_ro(amd_pstate_max_freq); > > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq); > > > > @@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf); > > cpufreq_freq_attr_rw(energy_performance_preference); > > cpufreq_freq_attr_ro(energy_performance_available_preferences); > > define_one_global_rw(pstate_dynamic_boost); > > +define_one_global_rw(status); > > > > static struct freq_attr *amd_pstate_attr[] = { > > &amd_pstate_max_freq, > > @@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = { > > > > static struct attribute *pstate_global_attributes[] = { > > &pstate_dynamic_boost.attr, > > + &status.attr, > > NULL > > }; > >
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