Re: CONFIG_PCIEASPM breaks PCIe on Marvell Armada 385 machine

[Russell King - ARM Linux <linux@armlinux.org.uk>]

On Wed, Jan 18, 2017 at 09:36:55AM -0800, David Daney wrote:
> On 01/18/2017 06:22 AM, Bjorn Helgaas wrote:
> The tricky thing here is assigning the blame for failure in link training.
> In the case in question we spent many months analysing the analog properties
> of the bus and examining/decoding  analog scope captures of the failures
> before credibly assigning blame to the other guy.  Usually what happens is
> the device vendor accurately claims that their device works flawlessly in
> conjunction with certain Intel root ports, so the problem must be fixed in
> the root port of the failing system.  If you have a black list, you may be
> disabling ASPM in systems where it can work without failures.

So what we need is not a table of just devices, but a combination of
devices... iow, "when root A and endpoint B are combined, retrains
need to be avoided."

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