On Thursday, January 05, 2017 03:42:20 PM Lukas Wunner wrote: > On Wed, Jan 04, 2017 at 10:09:54PM +0100, Peter Wu wrote: > > [ Help/ideas are welcome, I suspect that these failures to restore power > > on laptops designed for Win8+ all have the same cause, related to some > > unknown interaction between ACPI and PCI. Some links: > > https://bugzilla.kernel.org/show_bug.cgi?id=190861 > > https://bugzilla.kernel.org/show_bug.cgi?id=156341 ] > > Looking at Kilian's acpidump again I notice that the methods to power > the GPU on or off (GPON / GPOF) are called from two places: > > - From the _PS0 and _PS3 methods of the GPU and > - from the _PR3 power resource of the root port above the GPU. > > In the former case they're called for pre Windows 2013 or if VDAD is true. > In the latter case they're called unconditionally but GPOF becomes a no-op > in the pre Windows 2013 case. > > This means that GPOF would be executed *twice* on Windows 2013+ if VDAD > is true. I could imagine this to cause issues. Right. Exactly my observation (http://marc.info/?l=linux-pci&m=148362622326066&w=2). So on (newer) Windows something is done in order to make it work in addition to the _PR3 _OSC handshake. So, I'd like to try to follow the Mika's suggestion to use the response we get from the _OSC handshake for \_SB and if that says "no _PR3", ignore power resources for PCIe ports at least. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
