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cpufreq/amd-pstate: Fix EPP return type and handle errors during initialization

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Currently, the EPP getter helper functions (msr_get_epp, shmem_get_epp, and
the static call wrapper amd_pstate_get_epp) return u8 or s16. This makes it
difficult to correctly propagate negative error values returned by the
underlying MSR read or CPPC helpers (such as rdmsrq_on_cpu or
cppc_get_epp_perf).

Modify the return type of these functions to int, allowing them to return
negative error codes properly.

Additionally, in amd_pstate_epp_cpu_init(), fetch the firmware-programmed
default EPP value and validate it before assigning it to the EPP variables.
If amd_pstate_get_epp() returns an error code, propagate the error and abort
the CPU initialization to prevent subsequent configuration failures.

Fixes: 555bbe67a6 ("cpufreq/amd-pstate: Convert all perf values to u8")
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>
Reviewed-by: K Prateek Nayak <kprateek.anayk@amd.com>
Link: https://lore.kernel.org/r/20260609073042.81275-2-scardracs@disroot.org
Signed-off-by: Mario Limonciello <superm1@kernel.org>
This commit is contained in:
Marco Scardovi 2026-06-09 09:29:03 +02:00 committed by Mario Limonciello
parent 8d31bb1451
commit 57476909c3
1 changed files with 12 additions and 4 deletions
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16
drivers/cpufreq/amd-pstate.c
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@ -199,7 +199,7 @@ static inline int get_mode_idx_from_str(const char *str, size_t size)
static DEFINE_MUTEX(amd_pstate_driver_lock);
static u8 msr_get_epp(struct amd_cpudata *cpudata)
static int msr_get_epp(struct amd_cpudata *cpudata)
{
u64 value;
int ret;
@ -215,12 +215,12 @@ static u8 msr_get_epp(struct amd_cpudata *cpudata)
DEFINE_STATIC_CALL(amd_pstate_get_epp, msr_get_epp);
static inline s16 amd_pstate_get_epp(struct amd_cpudata *cpudata)
static inline int amd_pstate_get_epp(struct amd_cpudata *cpudata)
{
return static_call(amd_pstate_get_epp)(cpudata);
}
static u8 shmem_get_epp(struct amd_cpudata *cpudata)
static int shmem_get_epp(struct amd_cpudata *cpudata)
{
u64 epp;
int ret;
@ -1876,6 +1876,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
struct amd_cpudata *cpudata;
union perf_cached perf;
struct device *dev;
int default_epp;
int ret;
/*
@ -1924,6 +1925,13 @@ 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 */
default_epp = amd_pstate_get_epp(cpudata);
if (default_epp < 0) {
ret = default_epp;
goto free_cpudata1;
}
/*
* Set the policy to provide a valid fallback value in case
* the default cpufreq governor is neither powersave nor performance.
@ -1931,7 +1939,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
if (amd_pstate_acpi_pm_profile_server() ||
amd_pstate_acpi_pm_profile_undefined()) {
policy->policy = CPUFREQ_POLICY_PERFORMANCE;
cpudata->epp_default_ac = cpudata->epp_default_dc = amd_pstate_get_epp(cpudata);
cpudata->epp_default_ac = cpudata->epp_default_dc = default_epp;
cpudata->current_profile = PLATFORM_PROFILE_PERFORMANCE;
} else {
policy->policy = CPUFREQ_POLICY_POWERSAVE;