Re: How to find hotplug slot of PCI dev?

[Greg KH <greg@kroah.com>]

On Wed, Jun 29, 2005 at 07:14:43PM -0500, Linas Vepstas wrote:
> Yes, but a PCI error will take out *all* of the functions plugged into a
> slot.  It might even take out multiple slots, if the error occured on a
> cable connecting the CPU to the drawer with the pci cards in it.  

Then all of those pci_dev will get notified, right?  And if they all
start to try to power cycle the same card, bad things will probably
happen, right?

Again, refer to the PCI Hotplug spec for the fact that I do not think
this is allowable behaviour.

> Don't know anything about USB, but I assume that there is such a thing
> as a USB controller reset, and that will take out the entire chain
> until the reset completes.

There can be multiple USB controllers on a single PCI card, that are
independant of each other (much like network controllers can be.)

And USB 2.0 controllers have a built-in pci bridge with a USB 1.1
controller attached to it.  So it can be quite deep just at the PCI
layer.

> Its not all that much meaner than asserting the #RST line.  The point
> was that toggling the power was an effective way of dealing with device
> for which the device drivers don't support PCI error recovery.  But now 
> that I've got 5 drivers that do handle recovery, and some more in the
> works, maybe in fact I don't much need hotplug-based recovery any more, 
> and I could just let that drop.

Sounds like a wise thing :)

thanks,

greg k-h


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