Re: [ACPI] native vs acpi support

[vidyut k. <kvi...@ya...>]

Hi,
 
Section [6.7.8] of pci express specs related to OSHP says that

"Some systems that include Hot-Plug capable Root Ports and Switches that are released before ACPI-compliant operating systems with native Hot-Plug support are available, can use ACPI firmware for propagating Hot-Plug events. Firmware control of the Hot-Plug registers must be disabled if an operating system with native support is used. Platforms that provide ACPI firmware to propagate Hot-Plug events must also provide a control method to transfer control to the operating system."

 

I could not understand the above properly.Please help me understand this. If a OS is not ACPI compliant will it still be able to use the OSHP method provided by ACPI. Or does it mean that ACPI will disable the firmware taking control of Hot plug so that OS can take care of that.

 

Also in the native hotpluggin on PCI-Express how the control flows for ACPI and non-ACPI case. For e.g. in linux 2.6. 

 

Regards,

Karan

 


Rajesh Shah <raj...@in...> wrote:
On Mon, Sep 12, 2005 at 08:16:49AM +0100, vidyut karan wrote:
> 
> What is the difference betwwen an
> 
> OS with an "native hot plug support"
> 
An OS that has hotplug support as described in the PCI Express
specification. This is supported by the pciehp driver.

> and controlling the hot-plug by using ACPI.
> 
An OS that has hotplug support as described in the ACPI
specification. This is supported by the acpiphp driver.

Native pcie hotplug is newer and better, since it describes a
usage model (e.g. attention buttons, indicators etc.) and
standardizes the programming interface to the hotplug
hardware. 

> 
> If my query sounds idiotic, give me some pointers so that i can move
> on the right track.
> 
See the PCI hotplug specification and PCI Express specification
from the PCI SIG, and the ACPI specification from 
http://www.acpi.info/.

Rajesh

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