Re: Should a PCIe Link Down event set the PCI_DEV_DISCONNECTED bit?

[Lukas Wunner <lukas@wunner.de>]

On Mon, Jul 30, 2018 at 01:28:14PM +0000, David Laight wrote:
> From: Lukas Wunner
> > Sent: 28 July 2018 19:32
> ...
> > Finally, if the card was quickly swapped and the link to the new
> > card is already up, you may be accessing that new card.  (mmio
> > accesses may then still return all ones if the BARs are blank,
> > but at least config space accesses should work.)
> 
> On my i7-7700 system that no longer works (at least with some cards).
> If I take the PCIe link down completely (reset the FPGA on the card)
> it doesn't recover (loops through detect active/quiet and a third
> state I can't quite remember).
> 
> ISTR that it recovers from the link going down when I short out
> the PCIe data lines.
> 
> It worked fine on a XEON E5-2609 system - I did it a lot when
> updating the fpga image.
> 
> Can anyone else verify whether this works on other systems?
> Or whether the kernel (or BIOS) needs to (re-)initialise
> some register to make link recovery work.

Huh?  Can you be a bit more specific what exactly no longer works
and which branch or kernel version introduced the regression?

Thanks,

Lukas