Re: [PATCH 2/4] xhci: turn off port power in shutdown

[Joey Corleone <joey.corleone@mail.ru>]

On 23.06.22 13:19, Mathias Nyman wrote:
> If ports are not turned off in shutdown then runtime suspended
> self-powered USB devices may survive in U3 link state over S5.
> 
> During subsequent boot, if firmware sends an IPC command to program
> the port in DISCONNECT state, it will time out, causing significant
> delay in the boot time.
> 
> Turning off roothub port power is also recommended in xhci
> specification 4.19.4 "Port Power" in the additional note.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> ---
>   drivers/usb/host/xhci-hub.c |  2 +-
>   drivers/usb/host/xhci.c     | 15 +++++++++++++--
>   drivers/usb/host/xhci.h     |  2 ++
>   3 files changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
> index c54f2bc23d3f..0fdc014c9401 100644
> --- a/drivers/usb/host/xhci-hub.c
> +++ b/drivers/usb/host/xhci-hub.c
> @@ -652,7 +652,7 @@ struct xhci_hub *xhci_get_rhub(struct usb_hcd *hcd)
>    * It will release and re-aquire the lock while calling ACPI
>    * method.
>    */
> -static void xhci_set_port_power(struct xhci_hcd *xhci, struct usb_hcd *hcd,
> +void xhci_set_port_power(struct xhci_hcd *xhci, struct usb_hcd *hcd,
>   				u16 index, bool on, unsigned long *flags)
>   	__must_hold(&xhci->lock)
>   {
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index cb99bed5f755..65858f607437 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -791,6 +791,8 @@ static void xhci_stop(struct usb_hcd *hcd)
>   void xhci_shutdown(struct usb_hcd *hcd)
>   {
>   	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> +	unsigned long flags;
> +	int i;
>   
>   	if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
>   		usb_disable_xhci_ports(to_pci_dev(hcd->self.sysdev));
> @@ -806,12 +808,21 @@ void xhci_shutdown(struct usb_hcd *hcd)
>   		del_timer_sync(&xhci->shared_hcd->rh_timer);
>   	}
>   
> -	spin_lock_irq(&xhci->lock);
> +	spin_lock_irqsave(&xhci->lock, flags);
>   	xhci_halt(xhci);
> +
> +	/* Power off USB2 ports*/
> +	for (i = 0; i < xhci->usb2_rhub.num_ports; i++)
> +		xhci_set_port_power(xhci, xhci->main_hcd, i, false, &flags);
> +
> +	/* Power off USB3 ports*/
> +	for (i = 0; i < xhci->usb3_rhub.num_ports; i++)
> +		xhci_set_port_power(xhci, xhci->shared_hcd, i, false, &flags);
> +
>   	/* Workaround for spurious wakeups at shutdown with HSW */
>   	if (xhci->quirks & XHCI_SPURIOUS_WAKEUP)
>   		xhci_reset(xhci, XHCI_RESET_SHORT_USEC);
> -	spin_unlock_irq(&xhci->lock);
> +	spin_unlock_irqrestore(&xhci->lock, flags);
>   
>   	xhci_cleanup_msix(xhci);
>   
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index 0bd76c94a4b1..28aaf031f9a8 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -2196,6 +2196,8 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
>   int xhci_hub_status_data(struct usb_hcd *hcd, char *buf);
>   int xhci_find_raw_port_number(struct usb_hcd *hcd, int port1);
>   struct xhci_hub *xhci_get_rhub(struct usb_hcd *hcd);
> +void xhci_set_port_power(struct xhci_hcd *xhci, struct usb_hcd *hcd, u16 index,
> +			 bool on, unsigned long *flags);
>   
>   void xhci_hc_died(struct xhci_hcd *xhci);
>   

fyi: there is a report [1] about a regression introduced by this patch.

Joey

[1] https://bugzilla.kernel.org/show_bug.cgi?id=216243