From 55151d7daba185f94e9dc561a5a2ba36b5f647dd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 12 Aug 2008 14:33:59 -0400 Subject: USB: Defer Set-Interface for suspended devices This patch (as1128) fixes one of the problems related to the new PM infrastructure. We are not allowed to register new child devices during the middle of a system sleep transition, but unbinding a USB driver causes the core to automatically install altsetting 0 and thereby create new endpoint pseudo-devices. The patch fixes this problem (and the related problem that installing altsetting 0 will fail if the device is suspended) by deferring the Set-Interface call until some later time when it is legal and can succeed. Possible later times are: when a new driver is being probed for the interface, and when the interface is being resumed. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/driver.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index ed1cc8530a9..637b2bea556 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -230,6 +230,13 @@ static int usb_probe_interface(struct device *dev) */ intf->pm_usage_cnt = !(driver->supports_autosuspend); + /* Carry out a deferred switch to altsetting 0 */ + if (intf->needs_altsetting0) { + usb_set_interface(udev, intf->altsetting[0]. + desc.bInterfaceNumber, 0); + intf->needs_altsetting0 = 0; + } + error = driver->probe(intf, id); if (error) { mark_quiesced(intf); @@ -266,8 +273,17 @@ static int usb_unbind_interface(struct device *dev) driver->disconnect(intf); - /* reset other interface state */ - usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0); + /* Reset other interface state. + * We cannot do a Set-Interface if the device is suspended or + * if it is prepared for a system sleep (since installing a new + * altsetting means creating new endpoint device entries). + * When either of these happens, defer the Set-Interface. + */ + if (!error && intf->dev.power.status == DPM_ON) + usb_set_interface(udev, intf->altsetting[0]. + desc.bInterfaceNumber, 0); + else + intf->needs_altsetting0 = 1; usb_set_intfdata(intf, NULL); intf->condition = USB_INTERFACE_UNBOUND; @@ -975,8 +991,17 @@ static int usb_resume_interface(struct usb_device *udev, goto done; /* Can't resume it if it doesn't have a driver. */ - if (intf->condition == USB_INTERFACE_UNBOUND) + if (intf->condition == USB_INTERFACE_UNBOUND) { + + /* Carry out a deferred switch to altsetting 0 */ + if (intf->needs_altsetting0 && + intf->dev.power.status == DPM_ON) { + usb_set_interface(udev, intf->altsetting[0]. + desc.bInterfaceNumber, 0); + intf->needs_altsetting0 = 0; + } goto done; + } /* Don't resume if the interface is marked for rebinding */ if (intf->needs_binding) -- cgit v1.2.3