On Tue, Aug 27, 2019 at 4:50 AM Daniel Drake <drake@xxxxxxxxxxxx> wrote: > > On Mon, Aug 26, 2019 at 9:32 PM Mathias Nyman > <mathias.nyman@xxxxxxxxxxxxxxx> wrote: > > On 26.8.2019 12.29, Rafael J. Wysocki wrote: > > > I wonder if you can reproduce this with the pm-s2idle-rework branch > > > from linux-pm.git merged in. > > > > Root cause looks similar to: > > https://bugzilla.kernel.org/show_bug.cgi?id=203885 > > > > Mika wrote a fix for that: > > https://lore.kernel.org/linux-pci/20190821124519.71594-1-mika.westerberg@xxxxxxxxxxxxxxx/ > > Thanks for the suggestions. Mika's patch was already applied then > reverted, I applied it again but there's no change. > Also merging in pm-s2idle-rework doesn't make any difference. > > Any other ideas? Or comments on my findings so far? > Given that I can't shift D0-D3-D0 reliably directly with setpci before > loading the driver, is that indicative of a fundamental problem with > the platform, or is my test invalid? That depends on what exactly happens when you try to do the D0-D3-D0 with setpci. If the device becomes unreachable (or worse) after that, it indicates a platform issue. It should not do any harm at the least. However, in principle D0-D3-D0 at the PCI level alone may not be sufficient, because ACPI may need to be involved. I think that PM-runtime should suspend XHCI controllers without anything on the bus under them, so I wonder what happens if ".../power/control" is set to "on" and then to "auto" for that device, with the driver loaded. > Or in terms of other ways of testing the power transition outside of > the suspend path, if a PCI dev is runtime suspended with no driver > loaded, should Linux not be attempting to put it into D3? PCI devices without drivers cannot be runtime-suspended at all. Cheers, Rafael
