On Tue, Mar 12, 2024 at 10:08:16AM +0100, Mariusz Tkaczyk wrote: > On Mon, 11 Mar 2024 17:30:06 -0500 > Stuart Hayes <stuart.w.hayes@xxxxxxxxx> wrote: > > > > > No, Linux doesn't support _DSM. It was proposed in previous > > > > iterations by Stuart but I dropped it. We decided that it need to be > > > > strongly rebuild because "pci/pcie" is not right place for ACPI code > > > > so we cannot register _DSM driver instead of NPEM as it was proposed > > > > and I don't have _DSM capable hardware to test it. > > > > I'm not sure I understand why pci/pcie isn't the right place for ACPI code-- > > there are other _DSMs used in PCI code already, and this _DSM is defined > > in a PCI ECN. > > I looked into internal review history and I found out that I dropped it after > discussion with Dan Williams: > > > After review and discussion with Dan _DSM extension is dropped. > > Unfortunately, I don't remember what exactly he suggested, I just remembered > conclusion that it needs to be reworked and I decided to drop it. > Maybe, I didn't understand him correctly. > > Dan, could you take a look? Do you remember something? Straw man proposal: - Update this patch so we use NPEM if the device advertises it. - If/when Linux support for the _DSM is added, we use the _DSM when present. If a device advertises NPEM but no _DSM applies to it, we use native NPEM for it. Bjorn