[PATCH 3.4 040/107] xhci: prevent bus_suspend if SS port resuming in phase 1

lizf
2016-03-16T08:09:28Z

From: Zhuang Jin Can <jin.can.zhuang@intel.com>

3.4.111-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit fac4271d1126c45ceaceb7f4a336317b771eb121 upstream.

When the link is just waken, it's in Resume state, and driver sets PLS to
U0. This refers to Phase 1. Phase 2 refers to when the link has completed
the transition from Resume state to U0.

With the fix of xhci: report U3 when link is in resume state, it also
exposes an issue that usb3 roothub and controller can suspend right
after phase 1, and this causes a hard hang in controller.

To fix the issue, we need to prevent usb3 bus suspend if any port is
resuming in phase 1.

[merge separate USB2 and USB3 port resume checking to one -Mathias]
Signed-off-by: Zhuang Jin Can <jin.can.zhuang@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/usb/host/xhci-hub.c | 6 +++---
drivers/usb/host/xhci-ring.c | 3 +++
drivers/usb/host/xhci.h | 1 +
3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 9be0c29..fbbb11d 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1011,10 +1011,10 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
spin_lock_irqsave(&xhci->lock, flags);

if (hcd->self.root_hub->do_remote_wakeup) {
- if (bus_state->resuming_ports) {
+ if (bus_state->resuming_ports || /* USB2 */
+ bus_state->port_remote_wakeup) { /* USB3 */
spin_unlock_irqrestore(&xhci->lock, flags);
- xhci_dbg(xhci, "suspend failed because "
- "a port is resuming\n");
+ xhci_dbg(xhci, "suspend failed because a port is resuming\n");
return -EBUSY;
}
}
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 5e93425..b2afcb8 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1667,6 +1667,9 @@ static void handle_port_status(struct xhci_hcd *xhci,
usb_hcd_resume_root_hub(hcd);
}

+ if (hcd->speed == HCD_USB3 && (temp & PORT_PLS_MASK) == XDEV_INACTIVE)
+ bus_state->port_remote_wakeup &= ~(1 << faked_port_index);
+
if ((temp & PORT_PLC) && (temp & PORT_PLS_MASK) == XDEV_RESUME) {
xhci_dbg(xhci, "port resume event for port %d\n", port_id);

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 855f084..f4116fc 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -280,6 +280,7 @@ struct xhci_op_regs {
#define XDEV_U0 (0x0 << 5)
#define XDEV_U2 (0x2 << 5)
#define XDEV_U3 (0x3 << 5)
+#define XDEV_INACTIVE (0x6 << 5)
#define XDEV_RESUME (0xf << 5)
/* true: port has power (see HCC_PPC) */
#define PORT_POWER (1 << 9)
--
1.9.1