Questions tagged [acpi]

Advanced Configuration and Power Interface, a specification that provides an open standard for device configuration and power management by the operating system.

In computing, the Advanced Configuration and Power Interface (ACPI) specification provides an open standard for device configuration and by the operating system.

First released in December 1996, ACPI defines platform-independent interfaces for hardware discovery, configuration, power management and monitoring. With the intention of replacing Advanced Power Management, the MultiProcessor Specification and the Plug and Play BIOS Specification, the standard brings power management under the control of the operating system, as opposed to the previous BIOS-central system which relied on platform-specific firmware to determine power management and configuration policy. The specification is central to Operating System-directed configuration and Power Management (OSPM), a system implementing ACPI which removes device management responsibilities from legacy firmware interfaces.

The standard was originally developed by Intel, Microsoft and Toshiba, and was later joined by HP and Phoenix. As the ACPI technology gained wider adoption with many operating systems and processor architectures, the desire to improve the governance model of the specification has increased significantly. In October 2013, original developers of the ACPI standard agreed to transfer all assets to the Forum, where all future development will be taking place.3 The latest version of the standard is "Revision 6.2 Errata A", which was published by the UEFI Forum in September 2017.

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Is there a way to get battery info (status, plugged in, etc) without reading a proc/sys file on linux?

I want to get information about the battery in C on linux. I don't want to read or parse any file! Is there any low-level interface to acpi/the kernel or any other module to get the information I want to have? I already searched the web, but every…
musicmatze
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How to get string descriptor from a USB device which is in low power state?

I am trying to write an application in C++ which lists Information obtained from a USB device. I am following USBView (Github) utility's code for it. When device is in D0 power state (fully powered), I am able to get string descriptors, but when…
Sahil Singh
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Why do we need AML - ACPI Machine Language?

As I understand, ACPI defines a generic hardware programming model where operating system relies on the OEM firmware provided AML (ACPI machine language) code to manipulate the hardware. In order to execute the AML code, operating system has to…
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control FAN speed

I wanna control fan speed by C#. I tried WMI but it does not work for me :/ I have HP ProBook with Intel Core i5, Windows 7 HomePremium 64-bit. Is there any other way how to control fan speed (get temperature, set fan speed to higher or lower value…
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How to enable ACPI (for powering off) on LattePanda

I wrote this code to use ACPI for powering off computers from my program launched from 64-bit UEFI. (sorry for long code, but I think all parts are necessary) #include #define in8(data, port) __asm__ __volatile__ \ ("xor %%eax,…
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What does fwnode in struct device do in linux kernel?

In the definition of struct device,there is a fwnode field defined, struct device { ... struct fwnode_handle *fwnode; /* firmware device node */ ... } And the corresponding file is in include/linux/fwnode.h: struct…
downey
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How do I discover the ACPI id for a laptop touchpad in Linux?

How do I get the device ID for my touchpad in Linux? The device doesn't show up in lspci, lsusb, or cat /proc/bus/input/devices. For example, this patch adds the ID "ELAN0608": https://lkml.org/lkml/2017/8/10/145 I have a similar touchpad but I'm…
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Configure Linux to Suspend to Disk on ACPI G2 Soft Off -- so Google Compute Engine can suspend and restore preemptible machine via disk

Google Compute Engine rents all size Linux VMs from 1 core to 64 cores at various prices. There are "preempt-able" instances for about 1/4 the price of guaranteed instances, but the the preempt-able instances can be terminated at any time (with an…
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Use GPIO as chip select for SPI ACPI overlay

I want to use a GPIO pin as a new chip select for SPI on an Up Squared board. The Up squared uses an Intel Pentium N4200, so it's a x86 machine. I have managed to this on a Raspberry Pi by using Device Tree Overlays but as this is an x86 machine I…
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Does anyone know how to modify/disable the blinking power LED when OS enter into sleep mode?

Does anyone know how to modify/disable the blinking power LED when OS enter into sleep mode? Or is it feasible to do this by using OS? Does the power LED only controlled by hardware? Or OS could modify it? Thanks,
Fengwei Zhang
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Building a i2c device controller

I am building a PCB that will communicate via a i2c bus with a UDOO x86 running ubuntu 18.04 with two accesible i2c buses and multiple GPIO the device has 3 i2c chips on it i2c-mux-pca954x PCA9543 - level shifting bus switch SC18IS602B - i2c…
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Developing power consumption aware applications

Firstly, please don't move to serverfault. It is indeed a programming question :-) We are developing occasionally connected applications. These applications reside on laptop and handhelds. In my case, the application runs on a small servlet…
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In gnome w/ xmonad, how can I call a script when a monitor is plugged in OR when docking my laptop?

Problem: I have an extra set of top and bottom gnome-panels for a second monitor. When I undock my lenovo Thinkpad (T510), the extra top and bottom panels remain, so I have two on top and two on the bottom. I am currently running a RHEL6/Fedora…
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Cannot get ACPI GPEs and notifications to work

Recently, I've been working to get ACPI fully working on my x86 educational Linux-compatible kernel called Tilck. In order to that, I've integrated the latest version of ACPICA (ver. 20200717) and I've implemented the whole OS services layer. After…
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Where does ACPI hook into the shutdown sequence on linux to soft-off the PC?

Where can I hook into linux to add custom soft power down? That's the question. Here's why I need to know: I am trying to make a rapsberry pi soft power-down. More precisely I want the pi to be switched off (power supply disconnected) when put…
Philip Couling
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