Commit aa4ea34da9e7a2bc0fb98f5add3e4e52872b7d45
Committed by
Rafael J. Wysocki
Rafael J. Wysocki
1 parent
966916eabf
Exists in
ti-lsk-linux-4.1.y
and in
10 other branches
intel_pstate: add kernel parameter to force loading
To force loading on Oracle Sun X86 servers, provide one kernel command line parameter intel_pstate = force For those who are aware of the risk of no power capping capabily working and try to get better performance with this driver. Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com> Tested-by: Alexey Kodanev <alexey.kodanev@oracle.com> Reviewed-by: Linda Knippers <linda.knippers@hp.com> Acked-by: Kristen Carlson Accardi <kristen@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Showing 2 changed files with 14 additions and 1 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
| ... | ... | @@ -1446,6 +1446,15 @@ |
| 1446 | 1446 | disable |
| 1447 | 1447 | Do not enable intel_pstate as the default |
| 1448 | 1448 | scaling driver for the supported processors |
| 1449 | + force | |
| 1450 | + Enable intel_pstate on systems that prohibit it by default | |
| 1451 | + in favor of acpi-cpufreq. Forcing the intel_pstate driver | |
| 1452 | + instead of acpi-cpufreq may disable platform features, such | |
| 1453 | + as thermal controls and power capping, that rely on ACPI | |
| 1454 | + P-States information being indicated to OSPM and therefore | |
| 1455 | + should be used with caution. This option does not work with | |
| 1456 | + processors that aren't supported by the intel_pstate driver | |
| 1457 | + or on platforms that use pcc-cpufreq instead of acpi-cpufreq. | |
| 1449 | 1458 | no_hwp |
| 1450 | 1459 | Do not enable hardware P state control (HWP) |
| 1451 | 1460 | if available. |
drivers/cpufreq/intel_pstate.c
| ... | ... | @@ -948,6 +948,7 @@ |
| 948 | 948 | |
| 949 | 949 | static int __initdata no_load; |
| 950 | 950 | static int __initdata no_hwp; |
| 951 | +static unsigned int force_load; | |
| 951 | 952 | |
| 952 | 953 | static int intel_pstate_msrs_not_valid(void) |
| 953 | 954 | { |
| ... | ... | @@ -1094,7 +1095,8 @@ |
| 1094 | 1095 | case PSS: |
| 1095 | 1096 | return intel_pstate_no_acpi_pss(); |
| 1096 | 1097 | case PPC: |
| 1097 | - return intel_pstate_has_acpi_ppc(); | |
| 1098 | + return intel_pstate_has_acpi_ppc() && | |
| 1099 | + (!force_load); | |
| 1098 | 1100 | } |
| 1099 | 1101 | } |
| 1100 | 1102 | |
| ... | ... | @@ -1175,6 +1177,8 @@ |
| 1175 | 1177 | no_load = 1; |
| 1176 | 1178 | if (!strcmp(str, "no_hwp")) |
| 1177 | 1179 | no_hwp = 1; |
| 1180 | + if (!strcmp(str, "force")) | |
| 1181 | + force_load = 1; | |
| 1178 | 1182 | return 0; |
| 1179 | 1183 | } |
| 1180 | 1184 | early_param("intel_pstate", intel_pstate_setup); |