Fuchsia

zx_system_powerctl

Summary

TODO(fxbug.dev/32938)

Declaration

#include <zircon/syscalls.h>

zx_status_t zx_system_powerctl(zx_handle_t resource,
                               uint32_t cmd,
                               const zx_system_powerctl_arg_t* arg);

Description

zx_system_powerctl changes the power state of the system based on the value of cmd. Zircon may not be able to put the system in a given power state, depending on its level of support for the architecture being used.

arg is an optional pointer to a struct which provides further information about the command to be executed.

COMMANDS

ZX_SYSTEM_POWERCTL_ENABLE_ALL_CPUS

Sets all processor cores as active.

arg type: n/a

ZX_SYSTEM_POWERCTL_DISABLE_ALL_CPUS_BUT_PRIMARY

Set only the primary CPU as active.

arg type: n/a

ZX_SYSTEM_POWERCTL_ACPI_TRANSITION_S_STATE

Only defined for x86-64.

Currently only transitions to the S3 state are supported.

Before calling this syscall the following steps should be taken:

  1. Enter ACPICA noncontested mode
  2. Shut down the secondary CPUs
  3. Execute the _PTS control method
  4. (Optional) Execute the _SST control method
  5. Clear the ACPI wake status bit register
  6. Disable all ACPI GPEs
  7. Enabled all ACPI wakeup GPEs

arg type: zx_system_powerctl_arg_t with only the acpi_transition_s_state union element considered valid.

struct {
    uint8_t target_s_state;  // Value between 1 and 5 indicating which S-state
    uint8_t sleep_type_a;    // Value from ACPI VM (SLP_TYPa)
    uint8_t sleep_type_b;    // Value from ACPI VM (SLP_TYPb)
} acpi_transition_s_state;

Returns ZX_ERR_INVALID_ARGS if the target S state is not in the range 1-5.

Returns ZX_ERR_NOT_SUPPORTED if transitioning to the target S state is not supported.

Returns ZX_ERR_BAD_STATE if the target S state is not 5 and the secondary CPUs have not been shut down.

Returns ZX_ERR_NO_MEMORY if there are not enough resources to run the thread.

Returns ZX_ERR_INTERNAL if the S state transition fails.

ZX_SYSTEM_POWERCTL_X86_SET_PKG_PL1

Only defined for x86-64.

Set CPU to power level 1.

arg type: zx_system_powerctl_arg_t with only the x86_power_limit union element considered valid.

struct {
    uint32_t power_limit;  // PL1 value in milliwatts
    uint32_t time_window;  // PL1 time window in microseconds
    uint8_t clamp;         // PL1 clamping enable
    uint8_t enable;        // PL1 enable
    uint8_t padding2[2];
} x86_power_limit;

ZX_SYSTEM_POWERCTL_REBOOT

Restart the system, control should go through any relevant firmware and bootloaders.

arg type: n/a

ZX_SYSTEM_POWERCTL_REBOOT_BOOTLOADER

Restart the system, but stop in the bootloader instead of loading the operating system.

arg type: n/a

ZX_SYSTEM_POWERCTL_REBOOT_RECOVERY

Restart the system, but load the recovery operating system instead of the primary OS.

arg type: n/a

ZX_SYSTEM_POWERCTL_SHUTDOWN

Turn the system off.

arg type: n/a

ZX_SYSTEM_POWERCTL_ACK_KERNEL_INITIATED_REBOOT

Used by userspace when it is ready for a reboot in response to a previous signal from the kernel that the kernel wanted to reboot the system.

arg type: n/a

Returns ZX_ERR_BAD_STATE if the kernel has not previously signaled a desire to reboot.

Rights

resource must have resource kind ZX_RSRC_KIND_SYSTEM with base ZX_RSRC_SYSTEM_POWER_BASE.

Return value

ZX_OK

Errors

Returns ZX_ERR_INVALID_ARGS when an unrecognized cmd value is supplied.

See also

TODO(fxbug.dev/32938)