This is a note to let you know that I've just added the patch titled
cpufreq: amd-pstate: Add quirk for the pstate CPPC capabilities missing
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpufreq-amd-pstate-add-quirk-for-the-pstate-cppc-cap.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e2e92ece6fc62b33a603f527825d7c5f08ec5a2e
Author: Perry Yuan <perry.yuan@xxxxxxx>
Date: Thu Apr 25 16:07:58 2024 +0800
cpufreq: amd-pstate: Add quirk for the pstate CPPC capabilities missing
[ Upstream commit eb8b6c36820214df96e7e86d8614d93f6b028f28 ]
Add quirks table to get CPPC capabilities issue fixed by providing
correct perf or frequency values while driver loading.
If CPPC capabilities are not defined in the ACPI tables or wrongly
defined by platform firmware, it needs to use quick to get those
issues fixed with correct workaround values to make pstate driver
can be loaded even though there are CPPC capabilities errors.
The workaround will match the broken BIOS which lack of CPPC capabilities
nominal_freq and lowest_freq definition in the ACPI table.
$ cat /sys/devices/system/cpu/cpu0/acpi_cppc/lowest_freq
0
$ cat /sys/devices/system/cpu/cpu0/acpi_cppc/nominal_freq
0
Acked-by: Huang Rui <ray.huang@xxxxxxx>
Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Stable-dep-of: 779b8a14afde ("cpufreq: amd-pstate: remove global header file")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index e8385ca32f1fc..605b037913ff8 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -68,6 +68,7 @@ static struct cpufreq_driver amd_pstate_epp_driver;
static int cppc_state = AMD_PSTATE_UNDEFINED;
static bool cppc_enabled;
static bool amd_pstate_prefcore = true;
+static struct quirk_entry *quirks;
/*
* AMD Energy Preference Performance (EPP)
@@ -112,6 +113,41 @@ static unsigned int epp_values[] = {
typedef int (*cppc_mode_transition_fn)(int);
+static struct quirk_entry quirk_amd_7k62 = {
+ .nominal_freq = 2600,
+ .lowest_freq = 550,
+};
+
+static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
+{
+ /**
+ * match the broken bios for family 17h processor support CPPC V2
+ * broken BIOS lack of nominal_freq and lowest_freq capabilities
+ * definition in ACPI tables
+ */
+ if (boot_cpu_has(X86_FEATURE_ZEN2)) {
+ quirks = dmi->driver_data;
+ pr_info("Overriding nominal and lowest frequencies for %s\n", dmi->ident);
+ return 1;
+ }
+
+ return 0;
+}
+
+static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
+ {
+ .callback = dmi_matched_7k62_bios_bug,
+ .ident = "AMD EPYC 7K62",
+ .matches = {
+ DMI_MATCH(DMI_BIOS_VERSION, "5.14"),
+ DMI_MATCH(DMI_BIOS_RELEASE, "12/12/2019"),
+ },
+ .driver_data = &quirk_amd_7k62,
+ },
+ {}
+};
+MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);
+
static inline int get_mode_idx_from_str(const char *str, size_t size)
{
int i;
@@ -818,8 +854,16 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
if (ret)
return ret;
- min_freq = cppc_perf.lowest_freq * 1000;
- nominal_freq = cppc_perf.nominal_freq;
+ if (quirks && quirks->lowest_freq)
+ min_freq = quirks->lowest_freq * 1000;
+ else
+ min_freq = cppc_perf.lowest_freq * 1000;
+
+ if (quirks && quirks->nominal_freq)
+ nominal_freq = quirks->nominal_freq ;
+ else
+ nominal_freq = cppc_perf.nominal_freq;
+
nominal_perf = READ_ONCE(cpudata->nominal_perf);
highest_perf = READ_ONCE(cpudata->highest_perf);
@@ -1664,6 +1708,11 @@ static int __init amd_pstate_init(void)
if (cpufreq_get_current_driver())
return -EEXIST;
+ quirks = NULL;
+
+ /* check if this machine need CPPC quirks */
+ dmi_check_system(amd_pstate_quirks_table);
+
switch (cppc_state) {
case AMD_PSTATE_UNDEFINED:
/* Disable on the following configs by default:
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index d21838835abda..7b2cbb892fd91 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -124,4 +124,10 @@ static const char * const amd_pstate_mode_string[] = {
[AMD_PSTATE_GUIDED] = "guided",
NULL,
};
+
+struct quirk_entry {
+ u32 nominal_freq;
+ u32 lowest_freq;
+};
+
#endif /* _LINUX_AMD_PSTATE_H */
