On Tue, 1 Nov 2011, Sarah Sharp wrote:
> Linus, Keith, and Paul,
>
> Can you try the attached patch and see if it helps your issues with
> enabling runtime PM for the NEC USB 3.0 host controller? You may have
> to increase the timeout for your system.
>
>
> Hi Rafael,
>
> I mentioned I've been seeing failures when PCI runtime PM was enabled on
> the xHCI host controller in my Lenovo x220. It turns out that several
> people have the same NEC chipset in other Lenovo models, and are also
> experiencing similar issues. When runtime PM is enabled for the host,
> and you plug in a device, we get a steady stream of:
>
> Oct 31 16:11:31 puck kernel: [ 5196.504007] xhci_hcd 0000:0e:00.0: PME# enabled
> Oct 31 16:11:40 puck kernel: [ 5205.503185] xhci_hcd 0000:0e:00.0: PME# disabled
> Oct 31 16:11:40 puck kernel: [ 5205.503202] xhci_hcd 0000:0e:00.0: setting latency timer to 64
>
> Those three lines are repeated, but the new USB device never enumerates.
>
> I've discovered that if I add a small delay in the xhci_resume function
> (which is invoked by the dev_pm_ops resume method), then the host
> controller has time to issue an interrupt about the port status change
> before the runtime PM core puts it back into PCI suspend.
>
> I'm running Linus' latest tree as of yesterday (commit 839d8810), which
> includes your commit 379021d "PCI / PM: Extend PME polling to all PCI
> devices".
Here is the promised test patch. It doesn't involve adding any funny
delays. You might be able to improve this a little, but at least it
should get things to work properly.
Alan Stern
Index: usb-3.2/drivers/usb/host/xhci.c
===================================================================
--- usb-3.2.orig/drivers/usb/host/xhci.c
+++ usb-3.2/drivers/usb/host/xhci.c
@@ -799,7 +799,7 @@ int xhci_resume(struct xhci_hcd *xhci, b
u32 command, temp = 0;
struct usb_hcd *hcd = xhci_to_hcd(xhci);
struct usb_hcd *secondary_hcd;
- int retval;
+ int retval = 0;
/* Wait a bit if either of the roothubs need to settle from the
* transition into bus suspend.
@@ -809,6 +809,9 @@ int xhci_resume(struct xhci_hcd *xhci, b
xhci->bus_state[1].next_statechange))
msleep(100);
+ set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+ set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);
+
spin_lock_irq(&xhci->lock);
if (xhci->quirks & XHCI_RESET_ON_RESUME)
hibernated = true;
@@ -878,20 +881,13 @@ int xhci_resume(struct xhci_hcd *xhci, b
return retval;
xhci_dbg(xhci, "Start the primary HCD\n");
retval = xhci_run(hcd->primary_hcd);
- if (retval)
- goto failed_restart;
-
- xhci_dbg(xhci, "Start the secondary HCD\n");
- retval = xhci_run(secondary_hcd);
if (!retval) {
- set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
- set_bit(HCD_FLAG_HW_ACCESSIBLE,
- &xhci->shared_hcd->flags);
+ xhci_dbg(xhci, "Start the secondary HCD\n");
+ retval = xhci_run(secondary_hcd);
}
-failed_restart:
hcd->state = HC_STATE_SUSPENDED;
xhci->shared_hcd->state = HC_STATE_SUSPENDED;
- return retval;
+ goto done;
}
/* step 4: set Run/Stop bit */
@@ -910,11 +906,14 @@ failed_restart:
* Running endpoints by ringing their doorbells
*/
- set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
- set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);
-
spin_unlock_irq(&xhci->lock);
- return 0;
+
+ done:
+ if (retval == 0) {
+ usb_hcd_resume_root_hub(hcd);
+ usb_hcd_resume_root_hub(xhci->shared_hcd);
+ }
+ return retval;
}
#endif /* CONFIG_PM */
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
