Re: [PATCH 1/2] xhci: pci: If no ports have wakeup enabled then disable PCI device at S4

[Mario Limonciello <mario.limonciello@amd.com>]

On 8/21/2024 04:25, Mathias Nyman wrote:
> On 12.7.2024 21.54, superm1@kernel.org wrote:
>> From: Mario Limonciello <mario.limonciello@amd.com>
>>
>> If a port on an XHCI controller hasn't been marked for wakeup at S4, then
>> leaving it at D0 will needlessly consume power than necessary.
>>
>> Explicitly check ports configured for wakeup and if none are found then
>> put the controller into D3hot before hibernate.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>>   drivers/usb/host/xhci-pci.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>> index 05881153883ec..4408d4caf66d2 100644
>> --- a/drivers/usb/host/xhci-pci.c
>> +++ b/drivers/usb/host/xhci-pci.c
>> @@ -823,6 +823,7 @@ static int xhci_pci_poweroff_late(struct usb_hcd 
>> *hcd, bool do_wakeup)
>>       struct usb_device    *udev;
>>       u32            portsc;
>>       int            i;
>> +    bool            wakeup = false;
>>       /*
>>        * Systems with XHCI_RESET_TO_DEFAULT quirk have boot firmware that
>> @@ -860,6 +861,14 @@ static int xhci_pci_poweroff_late(struct usb_hcd 
>> *hcd, bool do_wakeup)
>>                port->rhub->hcd->self.busnum, port->hcd_portnum + 1);
>>           portsc = xhci_port_state_to_neutral(portsc);
>>           writel(portsc | PORT_PE, port->addr);
>> +        wakeup = true;
>> +    }
>> +
>> +    if (!wakeup) {
>> +        struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
>> +
>> +        xhci_shutdown(hcd);
>> +        pci_set_power_state(pdev, PCI_D3hot);
> 
> Not sure we should force D3 here.
> I think usb core will set the PCI D state in the next .poweroff_noirq 
> stage,
> 
> for s4:
> .poweroff    = hcd_pci_suspend,
> .poweroff_late    = hcd_pci_poweroff_late,
> .poweroff_noirq    = hcd_pci_suspend_noirq,
> 
> hcd_pci_suspend_noirq()
>    pci_prepare_to_sleep();
>      target_state = pci_target_state(dev, wakeup)
>      pci_set_power_state(dev, target_state)
> 
> Maybe the target_state isn't D3 for some reason? (missing ACPI entries?)
> 

Thanks for looking.

Even a lack of ACPI entries *should* still lead to D3hot if wakeup is 
turned off with that flow.

I'll add some more debugging for the various callbacks and see what I 
can come up with to explain it.

Can you please also review the other patch in the series?

Thanks!