Re: PCI extended tags regression: 3ware 9650SE-2LP RAID controller not working on AMD Ryzen system

[Sinan Kaya <okaya@kernel.org>]

On 2/1/2019 4:52 PM, Bjorn Helgaas wrote:
> See https://bugzilla.kernel.org/show_bug.cgi?id=202425.
> 
> Robert bisected a problem with a 3ware 9650SE-2LP controller to
> 60db3a4d8cc9 ("PCI: Enable PCIe Extended Tags if supported") and
> verified that reverting it solves the problem.
> 
> We have found issues in the past where Root Ports don't handle
> extended tags correctly and have added quirks to avoid use of them:
> 
>    1b30dfd376e2 ("PCI: Mark Broadcom HT1100 and HT2000 Root Port Extended Tags as broken")
>    62ce94a7a5a5 ("PCI: Mark Broadcom HT2100 Root Port Extended Tags as broken")
> 
> I don't know yet what Root Ports Robert has, but maybe we need a
> similar quirk?
> 
> I'm pretty sure Root Ports that don't handle extended tags are out of
> spec, so it would be ideal if we could get the manufacturer to provide
> an erratum as documentation.
> 

I agree. The issue needs to be directed to AMD. PCI spec says it is
safe to enable this option. I also have not heart of a single complaint
from Intel systems.


> Bjorn
>