[PATCH] ARM: Kirkwood: Support basic hotplug for PCI-E

Jason Gunthorpe jgunthorpe at obsidianresearch.com
Wed Nov 21 14:19:02 EST 2012


On Wed, Nov 21, 2012 at 08:02:30PM +0100, Andrew Lunn wrote:

> I think it may also cause problems with udev persistent rules. The IDs
> will change for devices which are on the second controller and the
> first controller was previously not registered. I've not idea if this
> is just a theoretical problem, or a real problem.

Most udev persistance rules I've seen are based on something more
permanent, like a MAC address or whatnot. The PCI-E bus number is
usually not used because it is historically not stable.

If a system is pluggable then the bus number already changes based on
what ports are plugged, so in a sense this patch makes things a bit
better by providing stable bus numbers.

When the PCI-E driver is integrated with DT it can get a busnr
resource range unique to each port and then the bus numbers will be
stable in almost all cases.

Jason



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