On 11/27/06, Takanori Watanabe <takawata@xxxxxxxxxxxxx> wrote:
In message <29545330611270227y4200182bkc9dfffbc62ab8d65@xxxxxxxxxxxxxx>, "Eric Benton" wrote: >Yeah, ok ;-) >Can you please describe the process of what happens when you decide to >switch the graphic adapter's screen? This is a bit complicated >example, but it will really help me understanding. For example, In a >Laptop, when you decide to switch from the LCD to an external VGA >screen? >It starts by a software request... I know all the handlers are defined >in the dsdt but, a description of the process (the handlers >registering + what events are being caused by software/hardware and >how is the hardware is related to the story) will help me finally >comprehend this... It's not always true. If your laptop supports video card output switching, it is not always implemented in AML. It should be implemented by video card's driver, not AML bytecode. But some laptops has BIOS request to do it. The request is invoked by SMI when some specific I/O port is accessed. Laptop extras device entity , implemented by AML, provides some method to put calling paramater to BIOS and access I/O port.Though, of cource, it is possible to access VGA card's register in AML.
Thanks for the replay Takanori, I stumbled upon this URL recently http://www.microsoft.com/whdc/device/display/mobiledisplay.mspx and so I asked for this example...
And how laptop extra's hotkey works is as follows: ACPI events are invoked by SCI. When SCI occured, appropriate interrupts are request and deliverd to ACPI driver, and the driver interpritet the source of SCI. When SCI gets GPIO event, it invokes AML methods bind to the event, eventually. In the method, Notify() object may be evaluated. When it is evaluated, ACPI driver invokes handler bounded to target of Notify() object. The handler handles the Notify and may propagate event to user, as a driver of laptop extra. I hope it may help you.
Yes, thank you for the example! Eric. - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
