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[Unstable,3/3] UBUNTU: SAUCE: cpufreq/amd-pstate: Get Highest Freq for a CPU

Message ID 20260917072851.29388-4-Leo.Lin@amd.com
State New
Headers show
Series Add support for CPPC values for Zen6 | expand

Commit Message

Yo-Jung Leo Lin \(AMD\) Sept. 17, 2026, 7:28 a.m. UTC 
From: Mario Limonciello <mario.limonciello@amd.com>

BugLink: https://bugs.launchpad.net/bugs/2167550

If the highest frequency is known for a CPU, use this instead of
trying to calculate by linear interpolation.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
(cherry picked from https://lore.kernel.org/linux-pm/20260901215913.3042182-4-mario.limonciello@amd.com)
Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index fc98e074ec7ec..228133af64ca3 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1017,8 +1017,10 @@  static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
 
 	WRITE_ONCE(cpudata->nominal_freq, nominal_freq);
 
-	/* max_freq is calculated according to (nominal_freq * highest_perf)/nominal_perf */
-	max_freq = perf_to_freq(perf, nominal_freq, perf.highest_perf);
+	/* try to look up from BIOS/quirk first, fall back to (nominal_freq * highest_perf)/nominal_perf */
+	max_freq = amd_get_max_frequency(cpudata->cpu) * 1000;
+	if (!max_freq)
+		max_freq = perf_to_freq(perf, nominal_freq, perf.highest_perf);
 	WRITE_ONCE(cpudata->max_freq, max_freq);
 
 	lowest_nonlinear_freq = perf_to_freq(perf, nominal_freq, perf.lowest_nonlinear_perf);