On Fri, 23 Mar 2012, Chen Peter-B29397 wrote:
> *************************************************************************************************************
> Index: usb-3.3/drivers/usb/core/hcd.c
> ===================================================================
> --- usb-3.3.orig/drivers/usb/core/hcd.c
> +++ usb-3.3/drivers/usb/core/hcd.c
> @@ -1978,6 +1978,13 @@ int hcd_bus_suspend(struct usb_device *r
> if (status == 0) {
> usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
> hcd->state = HC_STATE_SUSPENDED;
> +
> + /* Did we race with a root-hub wakeup event? */
> + if (unlikely(HCD_POLL_PENDING(hcd) &&
> + rhdev->do_remote_wakeup)) {
> + hcd_bus_resume(rhdev, PMSG_AUTO_RESUME);
> + status = -EBUSY;
> + }
>
> This patch may not useful, as if the remote wakeup occurs before the bus(roothub) suspend
> (taking ehic_bus_suspend as an example), the bus suspend will quit due to there is a resume
> signal at one port. If the remote wakeup occurs after bus suspend, but before your patch,
> the HCD_FLAG_POLL_PENDING will not be set due to hcd->driver->hub_status_data returns 0 (taking
> ehci as an example), as this flag is set after 25ms later after remote wakeup occurs.
I promised an update for this patch, and here it is. The new version
requires changes to the HCD drivers. Basically, the HCD is now
required to return a non-zero value from the hub_status_data routine if
a resume is currently in progress on any port. The changes for
ehci-hcd are included as a separate patch below.
Alan Stern
Index: usb-3.3/drivers/usb/core/hcd.c
===================================================================
--- usb-3.3.orig/drivers/usb/core/hcd.c
+++ usb-3.3/drivers/usb/core/hcd.c
@@ -1978,6 +1978,18 @@ int hcd_bus_suspend(struct usb_device *r
if (status == 0) {
usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
hcd->state = HC_STATE_SUSPENDED;
+
+ /* Did we race with a root-hub wakeup event? */
+ if (rhdev->do_remote_wakeup) {
+ char buffer[6];
+
+ status = hcd->driver->hub_status_data(hcd, buffer);
+ if (status != 0) {
+ dev_dbg(&rhdev->dev, "suspend raced with wakeup event\n");
+ hcd_bus_resume(rhdev, PMSG_AUTO_RESUME);
+ status = -EBUSY;
+ }
+ }
} else {
spin_lock_irq(&hcd_root_hub_lock);
if (!HCD_DEAD(hcd)) {
Index: usb-3.3/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-3.3.orig/drivers/usb/host/ehci-hub.c
+++ usb-3.3/drivers/usb/host/ehci-hub.c
@@ -223,15 +223,10 @@ static int ehci_bus_suspend (struct usb_
* remote wakeup, we must fail the suspend.
*/
if (hcd->self.root_hub->do_remote_wakeup) {
- port = HCS_N_PORTS(ehci->hcs_params);
- while (port--) {
- if (ehci->reset_done[port] != 0) {
- spin_unlock_irq(&ehci->lock);
- ehci_dbg(ehci, "suspend failed because "
- "port %d is resuming\n",
- port + 1);
- return -EBUSY;
- }
+ if (ehci->resuming_ports) {
+ spin_unlock_irq(&ehci->lock);
+ ehci_dbg(ehci, "suspend failed because a port is resuming\n");
+ return -EBUSY;
}
}
@@ -554,16 +549,12 @@ static int
ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
{
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
- u32 temp, status = 0;
+ u32 temp, status;
u32 mask;
int ports, i, retval = 1;
unsigned long flags;
u32 ppcd = 0;
- /* if !USB_SUSPEND, root hub timers won't get shut down ... */
- if (ehci->rh_state != EHCI_RH_RUNNING)
- return 0;
-
/* init status to no-changes */
buf [0] = 0;
ports = HCS_N_PORTS (ehci->hcs_params);
@@ -572,6 +563,11 @@ ehci_hub_status_data (struct usb_hcd *hc
retval++;
}
+ /* Inform the core about resumes-in-progress by returning
+ * a non-zero value even if there are no status changes.
+ */
+ status = ehci->resuming_ports;
+
/* Some boards (mostly VIA?) report bogus overcurrent indications,
* causing massive log spam unless we completely ignore them. It
* may be relevant that VIA VT8235 controllers, where PORT_POWER is
@@ -846,6 +842,7 @@ static int ehci_hub_control (
ehci_writel(ehci,
temp & ~(PORT_RWC_BITS | PORT_RESUME),
status_reg);
+ clear_bit(wIndex, &ehci->resuming_ports);
retval = handshake(ehci, status_reg,
PORT_RESUME, 0, 2000 /* 2msec */);
if (retval != 0) {
@@ -864,6 +861,7 @@ static int ehci_hub_control (
ehci->reset_done[wIndex])) {
status |= USB_PORT_STAT_C_RESET << 16;
ehci->reset_done [wIndex] = 0;
+ clear_bit(wIndex, &ehci->resuming_ports);
/* force reset to complete */
ehci_writel(ehci, temp & ~(PORT_RWC_BITS | PORT_RESET),
@@ -884,8 +882,10 @@ static int ehci_hub_control (
ehci_readl(ehci, status_reg));
}
- if (!(temp & (PORT_RESUME|PORT_RESET)))
+ if (!(temp & (PORT_RESUME|PORT_RESET))) {
ehci->reset_done[wIndex] = 0;
+ clear_bit(wIndex, &ehci->resuming_ports);
+ }
/* transfer dedicated ports to the companion hc */
if ((temp & PORT_CONNECT) &&
@@ -920,6 +920,7 @@ static int ehci_hub_control (
status |= USB_PORT_STAT_SUSPEND;
} else if (test_bit(wIndex, &ehci->suspended_ports)) {
clear_bit(wIndex, &ehci->suspended_ports);
+ clear_bit(wIndex, &ehci->resuming_ports);
ehci->reset_done[wIndex] = 0;
if (temp & PORT_PE)
set_bit(wIndex, &ehci->port_c_suspend);
Index: usb-3.3/drivers/usb/host/ehci.h
===================================================================
--- usb-3.3.orig/drivers/usb/host/ehci.h
+++ usb-3.3/drivers/usb/host/ehci.h
@@ -117,6 +117,8 @@ struct ehci_hcd { /* one per controlle
the change-suspend feature turned on */
unsigned long suspended_ports; /* which ports are
suspended */
+ unsigned long resuming_ports; /* which ports have
+ start to resume */
/* per-HC memory pools (could be per-bus, but ...) */
struct dma_pool *qh_pool; /* qh per active urb */
--
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