On Thu, Dec 6, 2018 at 1:05 PM Mauro Carvalho Chehab <mche...@kernel.org> wrote: > > Em Thu, 06 Dec 2018 18:18:23 +0100 > Markus Dobel <markus.do...@gmx.de> escreveu: > > > Hi everyone, > > > > I will try if the hack mentioned fixes the issue for me on the weekend (but > > I assume, as if effectively removes the function). > > It should, but it keeps a few changes. Just want to be sure that what > would be left won't cause issues. If this works, the logic that would > solve Ryzen DMA fixes will be contained into a single point, making > easier to maintain it. > > > > > Just in case this is of interest, I neither have Ryzen nor Intel, but an HP > > Microserver G7 with an AMD Turion II Neo N54L, so the machine is more on > > the slow side. > > Good to know. It would probably worth to check if this Ryzen > bug occors with all versions of it or with just a subset. > I mean: maybe it is only at the first gen or Ryzen and doesn't > affect Ryzen 2 (or vice versa).
The original commit also mentions some Xeons are affected too. Seems like this is potentially an issue on the device side rather than the platform. > > The PCI quirks logic will likely need to detect the PCI ID of > the memory controllers found at the buggy CPUs, in order to enable > the quirk only for the affected ones. > > It could be worth talking with AMD people in order to be sure about > the differences at the DMA engine side. > It's not clear to me what the pci or platform quirk would do. The workaround seems to be in the driver, not on the platform. Alex
