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From: "Yuan, Perry" <Perry.Yuan@amd.com>
To: "Limonciello, Mario" <Mario.Limonciello@amd.com>,
	"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
	"Huang, Ray" <Ray.Huang@amd.com>,
	"viresh.kumar@linaro.org" <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-pm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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	[thread overview]
Message-ID: <DM4PR12MB52789F0D712CEF9245E34A559C029@DM4PR12MB5278.namprd12.prod.outlook.com> (raw)
In-Reply-To: <72f8e103-b5d1-0def-685a-280b061fa759@amd.com>

[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
> >   };
> >

  reply	other threads:[~2022-11-13 16:18 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-07 17:56 [PATCH v3 0/8] Implement AMD Pstate EPP Driver Perry Yuan
2022-11-07 17:56 ` [PATCH v3 1/8] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2022-11-07 18:44   ` Limonciello, Mario
2022-11-10 14:49     ` Rafael J. Wysocki
2022-11-10 15:51       ` Yuan, Perry
2022-11-10 15:55         ` Rafael J. Wysocki
2022-11-10 16:23           ` Yuan, Perry
2022-11-13 16:28     ` Yuan, Perry
2022-11-07 17:56 ` [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles introduction Perry Yuan
2022-11-07 18:33   ` Limonciello, Mario
2022-11-13 16:23     ` Yuan, Perry
2022-11-10 14:57   ` Rafael J. Wysocki
2022-11-10 15:07     ` Yuan, Perry
2022-11-07 17:57 ` [PATCH v3 3/8] cpufreq: amd-pstate: change driver to be built-in type Perry Yuan
2022-11-07 18:29   ` Limonciello, Mario
2022-11-13 16:21     ` Yuan, Perry
2022-11-07 17:57 ` [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors Perry Yuan
2022-11-07 20:32   ` Limonciello, Mario
2022-11-10 15:59     ` Nathan Fontenot
2022-11-10 16:22       ` Yuan, Perry
2022-11-08  7:21   ` kernel test robot
2022-11-09  5:55   ` kernel test robot
2022-11-07 17:57 ` [PATCH v3 5/8] cpufreq: amd_pstate: implement amd pstate cpu online and offline callback Perry Yuan
2022-11-07 18:22   ` Limonciello, Mario
2022-11-13 16:19     ` Yuan, Perry
2022-11-07 17:57 ` [PATCH v3 6/8] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan
2022-11-07 18:18   ` Limonciello, Mario
2022-11-13 16:19     ` Yuan, Perry
2022-11-10 16:19   ` Nathan Fontenot
2022-11-07 17:57 ` [PATCH v3 7/8] cpufreq: amd-pstate: add frequency dynamic boost sysfs control Perry Yuan
2022-11-07 18:16   ` Limonciello, Mario
2022-11-07 19:09     ` Limonciello, Mario
2022-11-07 17:57 ` [PATCH v3 8/8] cpufreq: amd_pstate: add driver working mode status sysfs entry Perry Yuan
2022-11-07 18:10   ` Limonciello, Mario
2022-11-13 16:18     ` Yuan, Perry [this message]
2022-11-10 16:06   ` Nathan Fontenot
2022-11-10 16:49     ` Yuan, Perry

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