All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nathan Fontenot <nathan.fontenot@amd.com>
To: Perry Yuan <Perry.Yuan@amd.com>,
	rafael.j.wysocki@intel.com, ray.huang@amd.com,
	viresh.kumar@linaro.org
Cc: Deepak.Sharma@amd.com, Mario.Limonciello@amd.com,
	Alexander.Deucher@amd.com, Shimmer.Huang@amd.com,
	Xiaojian.Du@amd.com, Li.Meng@amd.com, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/8] cpufreq: amd-pstate: implement suspend and resume callbacks
Date: Thu, 10 Nov 2022 10:19:44 -0600	[thread overview]
Message-ID: <abc1fcce-3614-1896-5465-0249fb897702@amd.com> (raw)
In-Reply-To: <20221107175705.2207842-7-Perry.Yuan@amd.com>

On 11/7/22 11:57, Perry Yuan wrote:
> add suspend and resume support for the AMD processors by amd_pstate_epp
> driver instance.
> 
> When the CPPC is suspended, EPP driver will set EPP profile to 'power'
> profile and set max/min perf to lowest perf value.
> When resume happens, it will restore the MSR registers with
> previous cached value.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 40 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 6ce9fca0a128..841b1e2383b8 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1282,6 +1282,44 @@ static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
>  	return amd_pstate_cpu_offline(policy);
>  }
>  
> +static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
> +{
> +	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
> +	int ret;
> +
> +	/* avoid suspending when EPP is not enabled */
> +	if (!cppc_active)
> +		return 0;
> +
> +	/* set this flag to avoid setting core offline*/
> +	cpudata->suspended = true;

Shouldn't we set this only after the amd_pstate_enable(false) call succeeds?

> +
> +	/* disable CPPC in lowlevel firmware */
> +	ret = amd_pstate_enable(false);
> +	if (ret)
> +		pr_err("failed to suspend, return %d\n", ret);
> +
> +	return 0;

You could drop the checking of ret here and just return ret. The caller
cpufreq.c:cpufreq_suspend() already does a check of the return code and
prints an error message.

> +}
> +
> +static int amd_pstate_epp_resume(struct cpufreq_policy *policy)
> +{
> +	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
> +
> +	if (cpudata->suspended) {
> +		mutex_lock(&amd_pstate_limits_lock);
> +
> +		/* enable amd pstate from suspend state*/
> +		amd_pstate_epp_reenable(cpudata);

This call can fail, we should check the return code.

-Nathan

> +
> +		mutex_unlock(&amd_pstate_limits_lock);
> +
> +		cpudata->suspended = false;
> +	}
> +
> +	return 0;
> +}
> +
>  static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
>  					   struct cpufreq_policy_data *policy)
>  {
> @@ -1318,6 +1356,8 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
>  	.update_limits	= amd_pstate_epp_update_limits,
>  	.offline	= amd_pstate_epp_cpu_offline,
>  	.online		= amd_pstate_epp_cpu_online,
> +	.suspend	= amd_pstate_epp_suspend,
> +	.resume		= amd_pstate_epp_resume,
>  	.name		= "amd_pstate_epp",
>  	.attr		= amd_pstate_epp_attr,
>  };

  parent reply	other threads:[~2022-11-10 16:19 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 [this message]
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
2022-11-10 16:06   ` Nathan Fontenot
2022-11-10 16:49     ` Yuan, Perry

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=abc1fcce-3614-1896-5465-0249fb897702@amd.com \
    --to=nathan.fontenot@amd.com \
    --cc=Alexander.Deucher@amd.com \
    --cc=Deepak.Sharma@amd.com \
    --cc=Li.Meng@amd.com \
    --cc=Mario.Limonciello@amd.com \
    --cc=Perry.Yuan@amd.com \
    --cc=Shimmer.Huang@amd.com \
    --cc=Xiaojian.Du@amd.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=rafael.j.wysocki@intel.com \
    --cc=ray.huang@amd.com \
    --cc=viresh.kumar@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.