Documentation/ABI/testing/sysfs-firmware-acpi

Source file repositories/reference/linux-study-clean/Documentation/ABI/testing/sysfs-firmware-acpi

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/testing/sysfs-firmware-acpi
Extension
[no extension]
Size
9457 bytes
Lines
278
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/firmware/acpi/fpdt/
Date:		Jan 2021
Contact:	Zhang Rui <rui.zhang@intel.com>
Description:
		ACPI Firmware Performance Data Table (FPDT) provides
		information for firmware performance data for system boot,
		S3 suspend and S3 resume. This sysfs entry contains the
		performance data retrieved from the FPDT.

		boot:
			firmware_start_ns: Timer value logged at the beginning
				of firmware image execution. In nanoseconds.
			bootloader_load_ns: Timer value logged just prior to
				loading the OS boot loader into memory.
				In nanoseconds.
			bootloader_launch_ns: Timer value logged just prior to
				launching the currently loaded OS boot loader
				image. In nanoseconds.
			exitbootservice_start_ns: Timer value logged at the
				point when the OS loader calls the
				ExitBootServices function for UEFI compatible
				firmware. In nanoseconds.
			exitbootservice_end_ns: Timer value logged at the point
				just prior to the OS loader gaining control
				back from the ExitBootServices function for
				UEFI compatible firmware. In nanoseconds.
		suspend:
			suspend_start_ns: Timer value recorded at the previous
				OS write to SLP_TYP upon entry to S3. In
				nanoseconds.
			suspend_end_ns: Timer value recorded at the previous
				firmware write to SLP_TYP used to trigger
				hardware entry to S3. In nanoseconds.
		resume:
			resume_count: A count of the number of S3 resume cycles
				since the last full boot sequence.
			resume_avg_ns: Average timer value of all resume cycles
				logged since the last full boot sequence,
				including the most recent resume. In nanoseconds.
			resume_prev_ns: Timer recorded at the end of the previous
				platform runtime firmware S3 resume, just prior to
				handoff to the OS waking vector. In nanoseconds.

		FBPT: The raw binary contents of the Firmware Basic Boot
			Performance Table (FBPT) subtable.

		S3PT: The raw binary contents of the S3 Performance Table
			(S3PT) subtable.

What:		/sys/firmware/acpi/bgrt/
Date:		January 2012
Contact:	Matthew Garrett <mjg@redhat.com>
Description:
		The BGRT is an ACPI 5.0 feature that allows the OS
		to obtain a copy of the firmware boot splash and
		some associated metadata. This is intended to be used
		by boot splash applications in order to interact with
		the firmware boot splash in order to avoid jarring
		transitions.

		image: The image bitmap. Currently a 32-bit BMP.
		status: 1 if the image is valid, 0 if firmware invalidated it.
		type: 0 indicates image is in BMP format.

		======== ===================================================
		version: The version of the BGRT. Currently 1.
		xoffset: The number of pixels between the left of the screen
			 and the left edge of the image.
		yoffset: The number of pixels between the top of the screen
			 and the top edge of the image.

Annotation

Implementation Notes