@@ -280,16 +280,22 @@ A list of all the supported EPP preferences that could be used for
These profiles represent different hints that are provided
to the low-level firmware about the user's desired energy vs efficiency
tradeoff. ``default`` represents the epp value is set by platform
-firmware. This attribute is read-only.
+firmware. ``custom`` designates that integer values 0-255 may be written
+as well. This attribute is read-only.
``energy_performance_preference``
The current energy performance preference can be read from this attribute.
and user can change current preference according to energy or performance needs
-Please get all support profiles list from
-``energy_performance_available_preferences`` attribute, all the profiles are
-integer values defined between 0 to 255 when EPP feature is enabled by platform
-firmware, but if the dynamic EPP feature is enabled, driver will block writes.
+Coarse named profiles are available in the attribute
+``energy_performance_available_preferences``.
+Users can also write individual integer values between 0 to 255.
+When EPP feature is enabled by platform firmware but if the dynamic EPP feature is
+enabled, driver will ignore the written value. Lower epp values shift the bias
+towards improved performance while a higher epp value shifts the bias towards
+power-savings. The exact impact can change from one platform to the other.
+If a valid integer was last written, then a number will be returned on future reads.
+If a valid string was last written then a string will be returned on future reads.
This attribute is read-write.
``boost``
@@ -1330,6 +1330,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy,
struct amd_cpudata *cpudata = policy->driver_data;
char str_preference[21];
ssize_t ret;
+ bool raw_epp = FALSE;
u8 epp;
if (cpudata->dynamic_epp) {
@@ -1346,6 +1347,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy,
* matches an index in the energy_perf_strings array
*/
ret = kstrtou8(str_preference, 0, &epp);
+ raw_epp = !ret;
if (ret) {
ret = match_string(energy_perf_strings, -1, str_preference);
if (ret < 0 || ret == EPP_INDEX_CUSTOM)
@@ -1365,7 +1367,9 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy,
if (ret)
return ret;
- return ret ? ret : count;
+ cpudata->raw_epp = raw_epp;
+
+ return count;
}
EXPORT_SYMBOL_GPL(store_energy_performance_preference);
@@ -1376,6 +1380,9 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char *
epp = FIELD_GET(AMD_CPPC_EPP_PERF_MASK, cpudata->cppc_req_cached);
+ if (cpudata->raw_epp)
+ return sysfs_emit(buf, "%u\n", epp);
+
switch (epp) {
case AMD_CPPC_EPP_PERFORMANCE:
preference = EPP_INDEX_PERFORMANCE;
@@ -1390,7 +1397,7 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char *
preference = EPP_INDEX_POWERSAVE;
break;
default:
- return sysfs_emit(buf, "%u\n", epp);
+ return -EINVAL;
}
return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);
@@ -106,6 +106,7 @@ struct amd_cpudata {
u8 epp_default_ac;
u8 epp_default_dc;
bool dynamic_epp;
+ bool raw_epp;
struct notifier_block power_nb;
/* platform profile */