On Tue, Apr 22, 2025 at 8:28 AM Lukas Wunner <lukas@xxxxxxxxx> wrote: > > [cc += Rafael, linux-acpi] > > On Mon, Apr 21, 2025 at 10:05:59PM +0200, Heiner Kallweit wrote: > > If there's no platform support for transition to D3cold, then > > pci_set_power_state(dev, D3cold) still returns 0, even though > > power state is transitioned to D3hot only. We called > > pci_enable_wake(dev, D3cold, wakeup) before, therefore PME for > > D3hot may not be enabled. Is this a bug? On platforms using ACPI, no it isn't. Internally, pci_enable_wake() evaluates _DSW and it doesn't distinguish between D3hot and D3cold as per the spec. > > Background: > > In __pci_set_power_state we have the following: > > > > error = pci_set_low_power_state(dev, PCI_D3hot, locked); > > if (pci_platform_power_transition(dev, PCI_D3cold)) > > return error; > > > > The acpi_pci_set_power_state() stub returns -ENODEV. > > Therefore, if error=0, __pci_set_power_state() will > > return 0 if pci_platform_power_transition() fails. > > pci_prepare_to_sleep() calls pci_target_state() right at the top. > > If wakeup is supported and enabled, pci_target_state() is supposed > to find the deepest power state supporting wakeup. If D3cold doesn't > support wakeup, D3hot or a shallower state is returned. > > Hence I don't quite understand how the scenario you're describing > could occur in practice. Are you seeing actual issues and have tracked > them down to incorrect handling in pci_prepare_to_sleep()?
