On Fri, 24 Jul 2020 09:56:39 -0600 Logan Gunthorpe <logang@xxxxxxxxxxxx> wrote: > [+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. For non technical reasons, you can probably figure out, that particular ECR stalled. Unfortunately I can't directly provide info on any newer discussions. Eric, could you perhaps find out if there is anything we can share? This is the same question of trying to find a way to avoid white listing root complexes that can do peer 2 peer that would have been covered by your Advanced Peer to Peer Capabilities ECR. Thanks, Jonathan > > Logan
