diff options
| author | Marco Scardovi <scardracs@disroot.org> | 2026-06-09 09:29:05 +0200 |
|---|---|---|
| committer | Mario Limonciello <superm1@kernel.org> | 2026-07-22 13:45:48 -0500 |
| commit | d0f4c1c8cbffcfd5db683bd3f54396bfec12e9f5 (patch) | |
| tree | 0659f1f01a448ddf005421a11f8972bd0fbbd8a4 | |
| parent | 9dfd13f80c856eab79130403a13fa3b83199346b (diff) | |
| download | linux-next-d0f4c1c8cbffcfd5db683bd3f54396bfec12e9f5.tar.gz linux-next-d0f4c1c8cbffcfd5db683bd3f54396bfec12e9f5.zip | |
cpufreq/amd-pstate: Cache the firmware programmed EPP value
At CPU EPP initialization, the private cpudata structure is allocated via
kzalloc, which means cpudata->cppc_req_cached is initialized to 0. This
makes the default cached EPP value 0 (AMD_CPPC_EPP_PERFORMANCE).
When initializing a system that defaults to performance EPP, the driver
attempts to configure the EPP via amd_pstate_set_epp(). Because the
requested EPP (0) matches the uninitialized cached value (0), the cache
guard check triggers, and the driver skips writing to the hardware.
Cache the firmware-programmed default EPP value in cppc_req_cached during
CPU EPP initialization. This saves on an unnecessary reprogramming later
when the EPP is first set.
Assisted-by: Antigravity:gemini-3.5-flash
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Marco Scardovi <scardracs@disroot.org>
Link: https://lore.kernel.org/r/20260609073042.81275-4-scardracs@disroot.org
Signed-off-by: Mario Limonciello <superm1@kernel.org>
| -rw-r--r-- | drivers/cpufreq/amd-pstate.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 3c2995686a50..19d9e574ce5a 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -1922,12 +1922,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) policy->boost_supported = READ_ONCE(cpudata->boost_supported); - /* Fetch the firmware programmed default EPP value */ + /* Cache the firmware programmed EPP */ default_epp = amd_pstate_get_epp(cpudata); if (default_epp < 0) { ret = default_epp; goto free_cpudata1; } + FIELD_MODIFY(AMD_CPPC_EPP_PERF_MASK, &cpudata->cppc_req_cached, default_epp); /* * Set the policy to provide a valid fallback value in case |