Re: PCIe/PCI rescan for new FPGA devices

From: Greg KH
Date: Thu Apr 28 2011 - 22:29:00 EST


On Thu, Apr 28, 2011 at 06:06:50PM -0500, Xianghua Xiao wrote:
> I have a FPGA-PCIe device and a FPGA-PCI device that are empty at
> kernel boot time, they're only loaded after kernel is up. After I load
> FPGA images, "lspci" can not show the device, "echo 1 >
> /sys/bus/pci/rescan" also does nothing about it. With a reboot I can
> see the devices are allocated correctly though, but I want to avoid
> the reboot.
>
> I checked at fakephp(which is to be deprecated) and hotplug/rescan,
> none of that worked for this scenario.
>
> Can 'rescan' handle cases like this? or, is there a way that I tell
> the kernel to reserve a few BARs somehow in the PCI topology at
> bootime so I can "insert" the FPGAs later?

Your firmware has to do this, see the PCI hotplug specification for
details as to the proper procedure for this.

Best of luck,

greg k-h
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