On Wed, 11 Apr 2012, Chen Peter-B29397 wrote:
> > A better approach might be to have ehci_bus_resume check the port
> > statuses before turning on CMD_RUN, and re-suspend any enabled port
> > that isn't already suspended. Then when the controller starts sending
> > SOF packets, the host shouldn't think the device had disconnected.
> > Would that solve your problem?
What about this patch?
Alan Stern
drivers/usb/host/ehci-hub.c | 63 +++++++++++++++++++++++++++++++++++++++++---
1 file changed, 59 insertions(+), 4 deletions(-)
Index: usb-3.4/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-3.4.orig/drivers/usb/host/ehci-hub.c
+++ usb-3.4/drivers/usb/host/ehci-hub.c
@@ -329,6 +329,59 @@ static int ehci_bus_suspend (struct usb_
}
+static void ehci_resuspend_ports(struct ehci_hcd *ehci)
+{
+ u32 temp;
+ int i;
+ unsigned long resuspend_needed = 0;
+
+ /*
+ * If a remote wakeup request was received, the controller will
+ * already have begun resume signalling on that port. Some buggy
+ * controllers (e.g., Synopsys) automatically turn off the resume
+ * signal after 20 ms, leaving the port active and using high-speed
+ * signalling. But since CMD_RUN has been turned off, the device
+ * will not have received any SOF packets, so it will have gone
+ * back into suspend, using full-speed signalling. As a result,
+ * when the controller starts sending SOF packets again, it will
+ * think the device has disconnected.
+ *
+ * To avoid this problem, check to see if any enabled ports are
+ * resumed or resuming, and force them back into suspend before
+ * turning on CMD_RUN.
+ */
+ i = HCS_N_PORTS(ehci->hcs_params);
+ while (i--) {
+ temp = ehci_readl(ehci, &ehci->regs->port_status[i]);
+ temp &= ~(PORT_RWC_BITS | PORT_WAKE_BITS);
+ if ((temp & PORT_PE) && (!(temp & PORT_SUSPEND) ||
+ (temp & PORT_RESUME))) {
+ __set_bit(i, &resuspend_needed);
+ temp &= ~PORT_RESUME;
+ ehci_writel(ehci, temp, &ehci->regs->port_status[i]);
+ }
+ }
+
+ /* Give the port time to leave suspend, then resuspend it */
+ if (resuspend_needed) {
+ spin_unlock_irq(&ehci->lock);
+ msleep(3);
+ spin_lock_irq(&ehci->lock);
+
+ i = HCS_N_PORTS(ehci->hcs_params);
+ while (i--) {
+ if (test_bit(i, &resuspend_needed)) {
+ temp = ehci_readl(ehci,
+ &ehci->regs->port_status[i]);
+ temp &= ~PORT_RWC_BITS;
+ temp |= PORT_SUSPEND;
+ ehci_writel(ehci, temp,
+ &ehci->regs->port_status[i]);
+ }
+ }
+ }
+}
+
/* caller has locked the root hub, and should reset/reinit on error */
static int ehci_bus_resume (struct usb_hcd *hcd)
{
@@ -373,10 +426,6 @@ static int ehci_bus_resume (struct usb_h
ehci_writel(ehci, ehci->periodic_dma, &ehci->regs->frame_list);
ehci_writel(ehci, (u32) ehci->async->qh_dma, &ehci->regs->async_next);
- /* restore CMD_RUN, framelist size, and irq threshold */
- ehci_writel(ehci, ehci->command, &ehci->regs->command);
- ehci->rh_state = EHCI_RH_RUNNING;
-
/* Some controller/firmware combinations need a delay during which
* they set up the port statuses. See Bugzilla #8190. */
spin_unlock_irq(&ehci->lock);
@@ -402,6 +451,12 @@ static int ehci_bus_resume (struct usb_h
spin_lock_irq(&ehci->lock);
}
+ ehci_resuspend_ports(ehci);
+
+ /* restore CMD_RUN, framelist size, and irq threshold */
+ ehci_writel(ehci, ehci->command, &ehci->regs->command);
+ ehci->rh_state = EHCI_RH_RUNNING;
+
/* manually resume the ports we suspended during bus_suspend() */
i = HCS_N_PORTS (ehci->hcs_params);
while (i--) {
--
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