acpiecdt(4) [netbsd man page]
ACPIEC(4) BSD Kernel Interfaces Manual ACPIEC(4) NAME
acpiec -- ACPI Embedded Controller SYNOPSIS
acpiec* at acpi? acpiecdt* at acpi? DESCRIPTION
The acpiec driver supports ACPI Embedded Controllers. An ACPI Embedded Controller (EC) is typically a small microprocessor that is responsible for various tasks related to ACPI. The primary task is to handle ACPI specific interrupts, which are mapped to so-called ACPI General Purpose Events (GPEs). Other possible functions include embedded access to other buses such as the iic(4). The ACPI specific events range from user initiated events to events triggered by the hardware. When such an event occurs, typically either a System Management Interrupt (SMI) or a System Control Interrupt (SCI) is raised. The latter is an active, visible, shareable, level inter- rupt. On most Intel chipsets SCI is hardwired to the interrupt number 9. The main task of an EC is to raise a system control interrupt. All GPEs generate SCIs. A typical example of the internal wiring of GPEs could involve gpio(4): when, e.g., the AC adapter is connected, a certain GPIO line becomes active, a given GPE is flagged, and a SCI interrupt is raised by the EC, leading to execution of ACPI machine code in order to locate the handler associated with the event. A corresponding driver, acpiacad(4) in this case, will finally finish the process- ing of the event. Due to the reasons described above, majority of ACPI specific drivers are dysfunctional without acpiec. It is therefore recommended that acpiec is always enabled, even though it may not be required on some older systems. SEE ALSO
acpi(4) HISTORY
The acpiec driver appeared in NetBSD 1.6. CAVEATS
Many machines depend on early attachment of acpiec. In such cases the information required by acpiec should be available as a separate and optional Embedded Controller Descriptor Table (ECDT). If an ECDT is not available or early attachment can not be carried out due other rea- sons, the initialization of the whole acpi(4) subsystem may be problematic. BSD
February 27, 2010 BSD
Check Out this Related Man Page
ACPIVGA(4) BSD Kernel Interfaces Manual ACPIVGA(4) NAME
acpivga -- ACPI Display Adapter and Output Devices SYNOPSIS
acpivga* at acpi? acpiout* at acpivga? DESCRIPTION
The acpivga driver provides generic support for brightness control and output switching, through ACPI video extensions. The ACPI specifica- tion requires that systems containing a built-in display adapter implement these extensions in their ACPI BIOS. The driver handles brightness hotkeys and display switch hotkeys. In addition, the following sysctl(8) read/write variables are provided (when hardware support is available): hw.acpi.acpivga0.bios_switch BIOS output switching policy. This boolean variable controls the behavior of the BIOS when a display switch hotkey is pressed. 1 the BIOS should automatically switch outputs, with no interaction from acpivga. 0 the BIOS should only notify acpivga of the desired output state changes. hw.acpi.acpiout0.brightness Brightness level. This integer variable typically ranges from 0 to 100, but any integer value is accepted (the driver uses the clos- est brightness level supported by the device). Please note, however, that future versions of acpivga may remove these sysctl(8) variables without prior notice. SEE ALSO
acpi(4), vga(4), sysctl(8) Microsoft Corporation, Mobile System Displays and Windows, Version 1.2c, http://www.microsoft.com/whdc/archive/mobiledisplay.mspx, December 4, 2001. HISTORY
The acpivga driver appeared in NetBSD 6.0. AUTHORS
Gregoire Sutre <gsutre@NetBSD.org> CAVEATS
The acpivga driver only supports PCI/PCI-X/PCI-E display adapters. Many ACPI BIOSes implement only part of the ACPI video extensions. In particular, display output switching via these extensions often does not work. For this reason, acpivga enables hw.acpi.acpivga0.bios_switch by default. If the display switch hotkey does not work with this default setting, try setting hw.acpi.acpivga0.bios_switch to 0. Brightness level should be controlled via wsconsctl(8) instead of sysctl(8). BSD
October 28, 2010 BSD