Re: [PATCH v2] usb: xhci: only set D3hot for pci device

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 13.11.2019 3.49, Henry Lin wrote:
> Xhci driver cannot call pci_set_power_state() on non-pci xhci host
> controllers. For example, NVIDIA Tegra XHCI host controller which acts
> as platform device with XHCI_SPURIOUS_WAKEUP quirk set in some platform
> hits this issue during shutdown.
> 

The XHCI_SPURIOUS_WAKEUP quirk both resets the controller at shutdown
and sets it to PCI D3 at remove/shutdown.

Is it so that the NVIDIA Tegra xHC just needs to be reset at shutdown?
The quirk is not set for Tegra xHC in current mainline kernel.

> Signed-off-by: Henry Lin <henryl@nvidia.com>
> ---
>   drivers/usb/host/xhci.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 6c17e3fe181a..61718b126d2b 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -791,8 +791,11 @@ static void xhci_shutdown(struct usb_hcd *hcd)
>   			readl(&xhci->op_regs->status));
>   
>   	/* Yet another workaround for spurious wakeups at shutdown with HSW */
> -	if (xhci->quirks & XHCI_SPURIOUS_WAKEUP)
> -		pci_set_power_state(to_pci_dev(hcd->self.sysdev), PCI_D3hot);
> +	if (xhci->quirks & XHCI_SPURIOUS_WAKEUP) {
> +		if (dev_is_pci(hcd->self.sysdev))
> +			pci_set_power_state(to_pci_dev(hcd->self.sysdev),
> +					PCI_D3hot);
> +	}

Agree that we shouldn't call PCI specific functions in the generic shutdown code.
Would be better if we could move the PCI parts to xhci-pci.c or hcd-pci.c

Maybe we need to add a xhci_pci_shutdown() function for the xhci pci driver
that could take care of the pci related shutdown quirks before calling
usb_hcd_pci_shutdown(), and call that instead of directly calling
usb_hcd_pci_shutdown().

-Mathias