Re: Re: Problem while inserting pciehp (PCI Express Hot-plug) driver

From: Kristen Accardi
Date: Thu Jul 28 2005 - 12:07:00 EST

On 7/28/05, Rajat Jain <rajat.noida.india@xxxxxxxxx> wrote:
> >
> > Hi Rajat, you can learn more about the OSHP method by reading the PCI
> > express spec. It is used to tell an ACPI bios that the OS will be
> > handling the hotplug events natively. It may be that your BIOS does
> > not allow native hotplug for pcie, in which case you need to be using
> > the acpiphp driver instead of the pciehp driver. You could just try
> > modprobing acpiphp and see if this will handle the hotplug events. A
> > recent version of lspci (which understands pcie) will tell you as well
> > if pcie hotplug capability is supported (lspci -vv).
> >
> Okay. I'm sorry but I'm not very clear with this. I'm just putting
> down here my understanding. So basically we have two mutually
> EXCLUSIVE hotplug drivers I can use for PCI Express:
> 1) "pciehp.ko" : We use this PCIE HP driver when our BIOS supports
> Native Hot-plug for PCI Express (which means that hot-plug will be
> handled by OS single handedly).
> 2) "acpiphp.ko" : We use this "generic" ACPI HP driver when BIOS
> allows only ITSELF to handle hot-plug events.

usually this is configurable. So, you can configure you BIOS to use
acpi to handle hot-plug, or you can allow the OS to handle it. Most
OS (from what I hear) don't actually implement native hotplug support,
so native hotplug support is probably not as big a priority for bios
writers as the acpi support. so, it doesn't surprise me to find some
that don't support native.

you can run the native hotplug driver on a system who's bios supports
acpi - if it provides the OSHP method, this tells the bios to allow
the OS to handle it.

> Is my understanding correct? I would appreciate if you could help me
> gain a grip on this.

i'm trying to gain a grip myself, as i've just started learning about
pcie :). someone else hopefully will correct me if i'm telling you
the wrong info.

> Thanks a lot for the useful info you gave. Provided me with a new
> direction to work on.
> Regards,
> Rajat

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