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| author | Sumeet Pawnikar <sumeet.r.pawnikar@intel.com> | 2020-07-16 23:14:55 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-07-27 14:17:36 +0200 |
| commit | 8365a898fe53f85529566501d3b3d88640b3975e (patch) | |
| tree | 7984171ae5c65ba430b85596592bbe39b4b4a1ea /Documentation/power | |
| parent | 0735069c5e49d3f4f5f92669fcc3882500c118e5 (diff) | |
| download | lwn-8365a898fe53f85529566501d3b3d88640b3975e.tar.gz lwn-8365a898fe53f85529566501d3b3d88640b3975e.zip | |
powercap: Add Power Limit4 support
Modern Intel Mobile platforms support power limit4 (PL4), which is
the SoC package level maximum power limit (in Watts). It can be used
to preemptively limits potential SoC power to prevent power spikes
from tripping the power adapter and battery over-current protection.
This patch enables this feature by exposing package level peak power
capping control to userspace via RAPL sysfs interface. With this,
application like DTPF can modify PL4 power limit, the similar way
of other package power limit (PL1).
As this feature is not tested on previous generations, here it is
enabled only for the platform that has been verified to work,
for safety concerns.
Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
Co-developed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/power')
| -rw-r--r-- | Documentation/power/powercap/powercap.rst | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/power/powercap/powercap.rst b/Documentation/power/powercap/powercap.rst index 7ae3b44c7624..e75d12596dac 100644 --- a/Documentation/power/powercap/powercap.rst +++ b/Documentation/power/powercap/powercap.rst @@ -167,11 +167,13 @@ For example:: package-0 --------- -The Intel RAPL technology allows two constraints, short term and long term, -with two different time windows to be applied to each power zone. Thus for -each zone there are 2 attributes representing the constraint names, 2 power -limits and 2 attributes representing the sizes of the time windows. Such that, -constraint_j_* attributes correspond to the jth constraint (j = 0,1). +Depending on different power zones, the Intel RAPL technology allows +one or multiple constraints like short term, long term and peak power, +with different time windows to be applied to each power zone. +All the zones contain attributes representing the constraint names, +power limits and the sizes of the time windows. Note that time window +is not applicable to peak power. Here, constraint_j_* attributes +correspond to the jth constraint (j = 0,1,2). For example:: @@ -181,6 +183,9 @@ For example:: constraint_1_name constraint_1_power_limit_uw constraint_1_time_window_us + constraint_2_name + constraint_2_power_limit_uw + constraint_2_time_window_us Power Zone Attributes ===================== |