[+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@xxxxxxxxxxxx> 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@xxxxxxxxxxxx> >>>>> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >>>>> Cc: Christian König <christian.koenig@xxxxxxx> >>>>> Cc: Huang Rui <ray.huang@xxxxxxx> >>>>> Cc: Alex Deucher <alexdeucher@xxxxxxxxx> >>>> >>>> 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
