On Tue, 4 Nov 2014, Lu Baolu wrote:
> xhci: clear root port wake on bits if controller isn't wake-up capable
>
> When system is being suspended, if host device is not wakeup capable,
> xhci_suspend() needs to clear all root port wake on bits. Otherwise,
> some platforms may generate spurious wakeup, even if PCI PME# is dis-
> abled.
>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 2a5d45b..cd57aae 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -35,6 +35,8 @@
> #define DRIVER_AUTHOR "Sarah Sharp"
> #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
>
> +#define PORT_WAKE_BITS (PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
> +
> /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
> static int link_quirk;
> module_param(link_quirk, int, S_IRUGO | S_IWUSR);
> @@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
> xhci_set_cmd_ring_deq(xhci);
> }
>
> +static void xhci_disable_port_wake_on_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);
> +}
> +
> /*
> * Stop HC (not bus-specific)
> *
> @@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci)
> xhci->shared_hcd->state != HC_STATE_SUSPENDED)
> return -EINVAL;
>
> + /* Clear root port wake on bits if not wakeup capable. */
> + if (!device_may_wakeup(hcd->self.controller))
> + xhci_disable_port_wake_on_bits(xhci);
> +
> /* Don't poll the roothubs on bus suspend. */
> xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
> clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
This is better but still wrong. Remember, this same code gets called
for system suspend _and_ for runtime suspend. During runtime suspend,
wakeup is always supposed to be turned on, even if device_may_wakeup()
is false. That's because device_may_wakeup() refers only to system
suspend. What you need to test is the do_wakeup flag, which should be
passed into xhci_suspend() by xhci_pci_suspend() and
xhci_plat_suspend().
Another problem is in the patch description and the comments. If
device_may_wakeup() returns false, it doesn't mean the controller isn't
wakeup-capable -- it means the controller isn't _allowed_ to wake up
the system. Those are two different things.
Finally, the code in xhci_disable_port_wake_on_bits() looks a little
peculiar -- I'm not sure about all those calls to
xhci_port_state_to_neutral(). But I'm not an expert on that; Mathias
will have to advise on it.
Alan Stern
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