From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rajesh Shah Date: Mon, 26 Sep 2005 17:03:14 +0000 Subject: Re: [ACPI] native vs acpi support Message-Id: <20050926100312.B3471@unix-os.sc.intel.com> List-Id: References: <20050912110025.A15668@unix-os.sc.intel.com> <20050924021044.61508.qmail@web35415.mail.mud.yahoo.com> In-Reply-To: <20050924021044.61508.qmail@web35415.mail.mud.yahoo.com>; from kvidyut2000@yahoo.co.in on Sat, Sep 24, 2005 at 03:10:44AM +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: vidyut karan Cc: Rajesh Shah , linux-hotplug-devel@lists.sourceforge.net, acpi-devel@lists.sourceforge.net, greg@kroah.com On Sat, Sep 24, 2005 at 03:10:44AM +0100, vidyut karan wrote: > > 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." > The _OSC/OSHP mechanism is there to allow a system to support hotplug on a variety of OS's, some with and some without native pcie hotplug capabilities. Firmware could boot with the assumption that it will control hotplug hardware and the OS will only support the older acpiphp way of doing hot-plug. Of course, this still requires acpiphp support in the OS. If the system ends up booting a version of OS that supports native pcie hotplug, it will run the OSHP method to tell the BIOS that the OS will now control hotplug hardware directly. After OSHP is run, the BIOS must not attempt to control hotplug hardware, and must not generate an ACPI interrupt when hotplug occurs. > > 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. No. > Or does it mean that ACPI will disable > the firmware taking control of Hot plug so that OS can take care of > that. > Yes. > > 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. > acpi interrupts are not generated any more for hotplug once native pcie hotplug is enabled. Rajesh ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel