On Wed, May 24, 2023 at 02:07:26PM -0500, Mario Limonciello wrote:
> Using a USB keyboard or mouse to wakeup the system from s2idle fails when
> that XHCI device is connected to a USB-C port for an AMD USB4 router.
nit: I think the correct is "xHCI" but no need to spin a new version
just for that.
> Due to commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> all PCIe ports go into D3 during s2idle.
>
> When specific root ports are put into D3 over s2idle on some AMD platforms
> it is not possible for the platform to properly identify wakeup sources.
> This happens whether the root port goes into D3hot or D3cold.
>
> Comparing registers between Linux and Windows 11 this behavior to put
> these specific root ports into D3 at suspend is unique to Linux. On an
> affected system Windows does not put those specific root ports into D3
> over Modern Standby.
>
> Windows doesn't put the root ports into D3 because root ports are not
> power manageable.
Probably better is to say:
Windows avoids putting Root Ports that are not power manageable (e.g do
not have platform firmware support) into low power states.
but again no need to respin just for that.
> Linux shouldn't assume root ports support D3 just because they're on a
> machine newer than 2015, the ports should also be deemed power manageable.
> Add an extra check explicitly for root ports to ensure D3 isn't selected
> for these ports.
>
> Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> Reported-by: Iain Lane <iain@xxxxxxxxxxxxxxxxxxx>
> Closes: https://forums.lenovo.com/t5/Ubuntu/Z13-can-t-resume-from-suspend-with-external-USB-keyboard/m-p/5217121
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
