Like U3 case, xHCI spec doesn't specify the upper bound of U0 transition
time. The 20ms is not enough for some devices.
Intead of polling PLS or PLC, we can facilitate the port change event to
know that the link transits to U0 is completed.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
drivers/usb/host/xhci-hub.c | 8 +++++++-
drivers/usb/host/xhci-mem.c | 1 +
drivers/usb/host/xhci-ring.c | 1 +
drivers/usb/host/xhci.h | 1 +
4 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 2b2e9d004dbf..07886a1bce62 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1310,11 +1310,17 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
spin_lock_irqsave(&xhci->lock, flags);
}
}
+ if (link_state == USB_SS_PORT_LS_U0)
+ reinit_completion(&ports[wIndex]->link_state_changed);
xhci_set_link_state(xhci, ports[wIndex], link_state);
spin_unlock_irqrestore(&xhci->lock, flags);
- msleep(20); /* wait device to enter */
+ if (link_state == USB_SS_PORT_LS_U0) {
+ if (!wait_for_completion_timeout(&ports[wIndex]->link_state_changed, msecs_to_jiffies(100)))
+ xhci_dbg(xhci, "missing U0 port change event for port %d-%d\n", hcd->self.busnum, wIndex + 1);
+ } else
+ msleep(20); /* wait device to enter */
spin_lock_irqsave(&xhci->lock, flags);
if (link_state == USB_SS_PORT_LS_U3) {
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 3b1388fa2f36..c760a28e3556 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2268,6 +2268,7 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
xhci->hw_ports[i].addr = &xhci->op_regs->port_status_base +
NUM_PORT_REGS * i;
xhci->hw_ports[i].hw_portnum = i;
+ init_completion(&xhci->hw_ports[i].link_state_changed);
}
xhci->rh_bw = kcalloc_node(num_ports, sizeof(*xhci->rh_bw), flags,
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d23f7408c81f..44d91a53bf07 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1677,6 +1677,7 @@ static void handle_port_status(struct xhci_hcd *xhci,
(portsc & PORT_PLS_MASK) == XDEV_U1 ||
(portsc & PORT_PLS_MASK) == XDEV_U2)) {
xhci_dbg(xhci, "resume SS port %d finished\n", port_id);
+ complete(&port->link_state_changed);