On Fri, Oct 2, 2020 at 8:57 AM Lukas Wunner <lukas@xxxxxxxxx> wrote: > > On Wed, Sep 23, 2020 at 02:15:09PM +0200, Lukas Wunner wrote: > > I've just taken a look at the ACPI dumps provided by Michal Rostecki > > and Arthur Borsboom in the Gitlab bugs linked below. The topology > > looks like this: > > > > 00:01.1 Root Port [\_SB.PCI0.GPP0] > > 01:00.0 Switch Upstream [\_SB.PCI0.GPP0.SWUS] > > 02:00.0 Switch Downstream [\_SB.PCI0.GPP0.SWUS.SWDS] > > 03:00.0 dGPU [\_SB.PCI0.GPP0.SWUS.SWDS.VGA] > > 03:00.1 dGPU Audio [\_SB.PCI0.GPP0.SWUS.SWDS.HDAU] > > > > The Root Port is hotplug-capable but is not suspended because we only > > allow that for Thunderbolt hotplug ports or root ports with Microsoft's > > HotPlugSupportInD3 _DSD property. However, that _DSD is not present > > in the ACPI dumps and the Root Port is obviously not a Thunderbolt > > port either. > > I took another, closer look at the ACPI tables and couldn't find anything > specific about the Root Port or the GPU below, save for Power Resources > and corresponding _PS0 / _PS3 methods in the Root Port's namespace. > > If a hotplug port is explicitly power manageable by ACPI through these > methods, it should be safe to suspend it to D3. I wouldn't be surprised > if that's what Windows does. So I've just submitted a patch to whitelist > such ports for D3. It has been tested successfully by two users with > affected laptops: > > https://lore.kernel.org/linux-pci/cea9071dc46025f0d89cdfcec0642b7bfa45968a.1601614985.git.lukas@xxxxxxxxx/ This looks reasonable to me. Please feel free a Reviewed-by from me to the patch pointed to by the link above. Cheers!
