Re: [PATCH 2/3] usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe

[Alan Stern]

On Fri, 31 Oct 2014, Lu Baolu wrote:

> xhci: clear root port wake on bits if controller isn't wake-up capable
> 
> When xHCI PCI host is suspended, if do_wakeup is false in xhci_pci_suspend,
> xhci_pci_suspend needs to clear all root port wake on bits. Otherwise some Intel
> platforms may get a spurious wakeup, even if PCI PME# is disabled.
> 
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
>  drivers/usb/host/xhci-pci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/usb/host/xhci.h     |  6 ++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 280dde9..3e7441a 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -27,6 +27,8 @@
>  #include "xhci.h"
>  #include "xhci-trace.h"
>  
> +#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
> +
>  /* Device for a quirk */
>  #define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
>  #define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
> @@ -126,6 +128,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
>  		 */
>  		xhci->quirks |= XHCI_SPURIOUS_REBOOT;
>  		xhci->quirks |= XHCI_AVOID_BEI;
> +		xhci->quirks |= XHCI_DISABLE_PORT_WOB;
>  	}
>  	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
>  	    (pdev->device == PCI_DEVICE_ID_INTEL_LYNXPOINT_XHCI ||
> @@ -279,6 +282,42 @@ static void xhci_pci_remove(struct pci_dev *dev)
>  }
>  
>  #ifdef CONFIG_PM
> +static void xhci_disable_port_wake_bits(struct xhci_hcd *xhci)
> +{
> +	int port_index;
> +	__le32 __iomem **port_array;
> +	unsigned long flags;
> +	u32 t1, t2;
> +
> +	spin_lock_irqsave(&xhci->lock, flags);
> +
> +	/* disble usb3 ports Wake bits*/
> +	port_index = xhci->num_usb3_ports;
> +	port_array = xhci->usb3_ports;
> +	while (port_index--) {
> +		t1 = readl(port_array[port_index]);
> +		t2 = xhci_port_state_to_neutral(t1);
> +		t2 &= ~PORT_WAKE_BITS;
> +		t1 = xhci_port_state_to_neutral(t1);
> +		if (t1 != t2)
> +			writel(t2, port_array[port_index]);
> +	}
> +
> +	/* disble usb2 ports Wake bits*/
> +	port_index = xhci->num_usb2_ports;
> +	port_array = xhci->usb2_ports;
> +	while (port_index--) {
> +		t1 = readl(port_array[port_index]);
> +		t2 = xhci_port_state_to_neutral(t1);
> +		t2 &= ~PORT_WAKE_BITS;
> +		t1 = xhci_port_state_to_neutral(t1);
> +		if (t1 != t2)
> +			writel(t2, port_array[port_index]);
> +	}
> +
> +	spin_unlock_irqrestore(&xhci->lock, flags);
> +}
> +
>  static int xhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
>  {
>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
> @@ -291,6 +330,9 @@ static int xhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
>  	if (xhci->quirks & XHCI_COMP_MODE_QUIRK)
>  		pdev->no_d3cold = true;
>  
> +	if (xhci->quirks & XHCI_DISABLE_PORT_WOB && !do_wakeup)
> +		xhci_disable_port_wake_bits(xhci);
> +
>  	return xhci_suspend(xhci);
>  }

There are two things wrong here.  First, this should not be a quirk.  
The Wake-On bits should be disabled whenever they aren't needed, on 
every controller.

Second, this code (or something like it) belongs in xhci.c or 
xhci-hub.c, not xhci-pci.c.  This is because it should apply to all 
xHCI controllers, not just the PCI-based ones.

(In fact, instead of disabling the Wake-On bits when the controller is 
suspended and do_wakeup is 0, it probably would be better to leave them 
disabled normally and then _enable_ them if do_wakeup is 1.)

Alan Stern

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