From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Mario Limonciello <mario.limonciello@amd.com>,
Huang Rui <ray.huang@amd.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: Perry Yuan <perry.yuan@amd.com>,
K Prateek Nayak <kprateek.nayak@amd.com>
Subject: [PATCH 5/6] cpufreq/amd-pstate: Use "epp_default_dc" as default when dynamic_epp is disabled
Date: Fri, 8 May 2026 05:17:47 +0000 [thread overview]
Message-ID: <20260508051748.10484-6-kprateek.nayak@amd.com> (raw)
In-Reply-To: <20260508051748.10484-1-kprateek.nayak@amd.com>
If "dynamic_epp" is disabled, the driver initialization and the default
EPP selection from sysfs currently sets the EPP based on the power
supply state of the system at that time but there is no power supply
callbacks registered to toggle it when the power supply state changes.
This can lead to faster battery drain on platforms that start off while
being plugged to the wall but later move to battery power since the EPP
stays at AMD_CPPC_EPP_PERFORMANCE.
Use "epp_default_dc" as the default EPP selection when dynamic_epp is
disabled, restoring older behavior. On servers, this defaults to
AMD_CPPC_EPP_PERFORMANCE and on other platforms, it defaults to
AMD_CPPC_EPP_BALANCE_PERFORMANCE.
Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference")
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
---
drivers/cpufreq/amd-pstate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 175925762a93c..9eb9c3f4e809a 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1429,7 +1429,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy,
if (ret)
epp = epp_values[ret];
else
- epp = amd_pstate_get_balanced_epp(policy);
+ epp = cpudata->epp_default_dc;
}
if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
@@ -1954,7 +1954,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
if (dynamic_epp)
ret = amd_pstate_set_dynamic_epp(policy);
else
- ret = amd_pstate_set_epp(policy, amd_pstate_get_balanced_epp(policy));
+ ret = amd_pstate_set_epp(policy, cpudata->epp_default_dc);
if (ret)
goto free_cpudata1;
--
2.34.1
next prev parent reply other threads:[~2026-05-08 5:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-08 5:17 [PATCH 0/6] cpufreq/amd-pstate: Dynamic EPP fixes K Prateek Nayak
2026-05-08 5:17 ` [PATCH 1/6] cpufreq/amd-pstate: Grab "amd_pstate_driver_lock" when toggling dynamic_epp K Prateek Nayak
2026-05-08 5:17 ` [PATCH 2/6] cpufreq/amd-pstate: Return -ENOMEM on failure to allocate profile_name K Prateek Nayak
2026-05-08 5:17 ` [PATCH 3/6] cpufreq/amd-pstate: Allow writes to dynamic_epp when state isn't modified K Prateek Nayak
2026-05-08 5:17 ` [PATCH 4/6] cpufreq/amd-pstate: Reorder notifier unregistration and floor perf reset K Prateek Nayak
2026-05-08 5:17 ` K Prateek Nayak [this message]
2026-05-08 5:17 ` [PATCH 6/6] cpufreq/amd-pstate-ut: Drop policy reference before driver switch K Prateek Nayak
2026-05-08 18:04 ` [PATCH 0/6] cpufreq/amd-pstate: Dynamic EPP fixes Mario Limonciello
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