> On Feb 4, 2019, at 6:20 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Sun, Feb 03, 2019 at 01:46:50AM +0800, Kai Heng Feng wrote: >>> On Jan 28, 2019, at 3:51 PM, Kai Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: >> >>>> If I understand correctly, the bugzilla lspci >>>> (https://bugzilla.kernel.org/attachment.cgi?id=280691) was collected >>>> at point 8, and it shows PME_Status=1 when it should be 0. >>>> >>>> If we write a 1 to PME_Status to clear it, and it remains set, that's >>>> obviously a hardware defect, and Intel should document that in an >>>> erratum, and a quirk would be the appropriate way to work around it. >>>> But I doubt that's what's happening. >>> >>> I’ll ask them if they can provide an erratum. >> >> Got confirmed with e1000e folks, I219 (the device in question) doesn’t >> really support runtime D3. > > Did you get a reference, e.g., an intel.com URL for that? Intel > usually publishes errata for hardware defects, which is nice because > it means every customer doesn't have to experimentally rediscover > them. Unfortunately no. > >> I also checked the behavior of the device under Windows, and it >> stays at D0 all the time even when it’s not in use. > > I think there are two possible explanations for this: > > 1) This device requires a Windows or a driver update with a > device-specific quirk similar to what you're proposing for Linux. I am sure the latest driver is loaded under Windows. > > 2) Windows correctly detects that this device doesn't support D3, > and Linux has a bug and does not detect that. I think that’s the case. > > Obviously nobody wants to require OS or driver updates just for minor > device changes, and the PCI and ACPI specs are designed to allow > generic, non device-specific code to detect D3 support, so the first > case should be a result of a hardware defect. Yea, that’s why my original idea is to workaround it in PCI/ACPI. > >> So I sent a patch [1] to disable it. >> >> [1] https://lkml.org/lkml/2019/2/2/200 > > OK. Since that's in drivers/net/..., I have no objection and the > e1000e maintainers would deal with that. Thanks. Kai-Heng > > Bjorn
