Messages in this thread | | | From | Logan Gunthorpe <> | Date | Fri, 24 Jul 2020 09:56:39 -0600 | Subject | Re: [PATCH] PCI/P2PDMA: Add AMD Zen 2 root complex to the list of allowed bridges |
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[+cc Jonathan]
On 2020-07-24 9:06 a.m., Bjorn Helgaas wrote: > On Thu, Jul 23, 2020 at 02:10:52PM -0600, Logan Gunthorpe wrote: >> On 2020-07-23 1:57 p.m., Bjorn Helgaas wrote: >>> On Thu, Jul 23, 2020 at 02:01:17PM -0400, Alex Deucher wrote: >>>> On Thu, Jul 23, 2020 at 1:43 PM Logan Gunthorpe <logang@deltatee.com> wrote: >>>>> >>>>> The AMD Zen 2 root complex (Starship/Matisse) was tested for P2PDMA >>>>> transactions between root ports and found to work. Therefore add it >>>>> to the list. >>>>> >>>>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> >>>>> Cc: Bjorn Helgaas <bhelgaas@google.com> >>>>> Cc: Christian König <christian.koenig@amd.com> >>>>> Cc: Huang Rui <ray.huang@amd.com> >>>>> Cc: Alex Deucher <alexdeucher@gmail.com> >>>> >>>> Starting with Zen, all AMD platforms support P2P for reads and writes. >>> >>> What's the plan for getting out of the cycle of "update this list for >>> every new chip"? Any new _DSMs planned, for instance? >> >> Well there was an effort to add capabilities in the PCI spec to describe >> this but, as far as I know, they never got anywhere, and hardware still >> doesn't self describe with this. > > Any idea what happened? Is there hope for the future? I'm really not > happy about signing up for open-ended device-specific patches like > this. It's certainly not in the plug and play spirit that has made > PCI successful. I know, preaching to the choir here.
Agreed, though I'm not really hooked into the PCI SIG. The last email I got about this was an RFC from Jonathan Cameron in late 2018. I've CC'd him here, maybe he'll have a bit more insight.
Logan
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