Modify UFS device power management states

For more information about how to run SSH, see the Connect over SSH section.

State	Description
Auto-hibern8 (AH8)	AH8 automatically transitions the PHY link to the Hibernate state after 150 ms of idle time. This value is adjustable. To determine the AH8 idle duration value (in microseconds), run the following SSH command on the host computer. `cat /sys/devices/platform/soc@0/1d84000.ufshc/auto_hibern8` This value can be decreased to reduce power consumption.
Clock gating	When UFS device clocks are scaled up to maximum frequency due to the use case, clocks are gated after 50 ms of idle duration. If clocks are scaled down to optimal frequency, clocks are gated after 10 ms of idle duration. To check clock gating enabled/disabled status, run the following SSH command on the host computer. `cat /sys/devices/platform/soc@0/1d84000.ufshc/clkgate_enable` Clock gating is enabled by default. To debug UFS device issues related to clock gate or ungate and to disable the clock gating, run the following SSH command on the host computer. `echo 0 > /sys/devices/platform/soc@0/1d84000.ufshc/clkgate_enable`
Clock scaling	After the UFS device load exceeds the upthreshold value, the clock frequency is set to the maximum frequency with clock scale up. Clock scale-down occurs when the load is lower than the threshold. The UFS device operations determines its load. To check the clock scaling status, run the following SSH command on the host computer. `cat /sys/devices/platform/soc@0/1d84000.ufshc/clkscale_enable` Clock scaling is enabled by default. Disabling clock scaling can result in increased power consumption. To debug any issue related to clock scaling, run the following SSH command on the host computer. `echo 0 > /sys/devices/platform/soc@0/1d84000.ufshc/clkscale_enable`
Runtime suspend or resume	UFS device enters the runtime suspend state after 3 seconds of inactivity. Runtime resume state occurs with the next UFS device operation. This state is enabled by default and is not configurable.
System suspend or resume	UFS device enters the system suspend with the suspend event. UFS device resume state occurs with the system resume event. This state is enabled by default and is not configurable.

State

Description

Auto-hibern8 (AH8)

AH8 automatically transitions the PHY link to the Hibernate state after 150 ms of idle time. This value is adjustable.
To determine the AH8 idle duration value (in microseconds), run the following SSH command on the host computer.
cat /sys/devices/platform/soc@0/1d84000.ufshc/auto_hibern8
This value can be decreased to reduce power consumption.

Clock gating

When UFS device clocks are scaled up to maximum frequency due to the use case, clocks are gated after 50 ms of idle duration.
If clocks are scaled down to optimal frequency, clocks are gated after 10 ms of idle duration. To check clock gating enabled/disabled status, run the following SSH command on the host computer.
cat /sys/devices/platform/soc@0/1d84000.ufshc/clkgate_enable
Clock gating is enabled by default.
To debug UFS device issues related to clock gate or ungate and to disable the clock gating, run the following SSH command on the host computer.
echo 0 > /sys/devices/platform/soc@0/1d84000.ufshc/clkgate_enable

Clock scaling

After the UFS device load exceeds the upthreshold value, the clock frequency is set to the maximum frequency with clock scale up.
Clock scale-down occurs when the load is lower than the threshold. The UFS device operations determines its load. To check the clock scaling status, run the following SSH command on the host computer.
cat /sys/devices/platform/soc@0/1d84000.ufshc/clkscale_enable
Clock scaling is enabled by default.
Disabling clock scaling can result in increased power consumption. To debug any issue related to clock scaling, run the following SSH command on the host computer.
echo 0 > /sys/devices/platform/soc@0/1d84000.ufshc/clkscale_enable

Runtime suspend or resume

UFS device enters the runtime suspend state after 3 seconds of inactivity.
Runtime resume state occurs with the next UFS device operation. This state is enabled by default and is not configurable.

System suspend or resume

UFS device enters the system suspend with the suspend event.
UFS device resume state occurs with the system resume event. This state is enabled by default and is not configurable.

Introduction

Architecture

Key Documents

Technologies

System

Release Notes