dvfs_client

Runs on:

QNX OS

Targets:

ARMv7

Options:

None.

Description:

The dvfs_client utility provides a way for you to interact with a dvfsmgr-* driver.

Run this utility with no options. It will register itself under /dev/dvfs_client_#, where # is the instance number of the client. You can have a maximum of nine concurrent DVFS clients.

Use echo and cat to send commands to the DVFS driver. For example, to read the driver's status:

# cat /dev/dvfs_client_1

You can set DVFS driver's mode like this:

echo option > /dev/dvfs_client_#

The option is one of:

• MM: set to manual mode.
• MS: set to semi-automatic mode.
• MA: set to automatic mode.

Change the power level like this:

echo level > /dev/dvfs_client_#

The level is one of:

• PU: increase the power level.
• PD: decrease the power level.
• PX: set the power level to the maximum.
• PM: set the power level to the minimum.

To set minimum level of performance:

echo Slevel > /dev/dvfs_client_#

To unset a previously set minimum level:

echo U > /dev/dvfs_client_#

The DVFS driver responds to the device control (devctl()) messages listed below. Some commands may be valid only for a certain driver mode, as indicated.

DVFS_DEVCTL_SET_MIN

Set the minimum level of power (automatic mode).

DVFS_DEVCTL_UNSET_MIN

Unset the minimum power level (automatic mode).

DVFS_DEVCTL_SET_MODE

Set the driver mode.

DVFS_DEVCTL_SET_PWR_LVL

Set the driver's power level (manual or semi-automatic).

DVFS_DEVCTL_GETSTATUS

Get the driver's status.

DVFS_DEVCTL_RUN_MAX

Run at the maximum power level (manual or semi-automatic).

DVFS_DEVCTL_RUN_MIN

Run at the minimum power level (manual or semi-automatic).