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

From: Mathias Nyman
Date: Wed Aug 21 2024 - 06:57:22 EST


On 12.7.2024 21.54, superm1@xxxxxxxxxx wrote:
From: Mario Limonciello <mario.limonciello@xxxxxxx>

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@xxxxxxx>
---
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
Mathias