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. > 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. 2) Windows correctly detects that this device doesn't support D3, and Linux has a bug and does not detect that. 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. > 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. Bjorn
