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authorAlan Stern <stern@rowland.harvard.edu>2010-01-08 11:18:20 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-01-28 15:20:37 -0800
commit4fbebe26d7a5eed6c1900bf2142b68af7df38462 (patch)
treed4da3dc295c34dbe65e4ffd9724ea05d13943eb2
parent5b3363926eed5839fdc84055d20f9153980d4b5f (diff)
USB: EHCI & UHCI: fix race between root-hub suspend and port resume
commit cec3a53c7fe794237b582e8e77fc0e48465e65ee upstream. This patch (as1321) fixes a problem with EHCI and UHCI root-hub suspends: If the suspend occurs while a port is trying to resume, the resume doesn't finish and simply gets lost. When remote wakeup is enabled, this is undesirable behavior. The patch checks first to see if any port resumes are in progress, and if they are then it fails the root-hub suspend with -EBUSY. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/ehci-hub.c20
-rw-r--r--drivers/usb/host/uhci-hcd.c15
2 files changed, 33 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 740835bb8575..ef9b0383fed3 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -119,9 +119,26 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
del_timer_sync(&ehci->watchdog);
del_timer_sync(&ehci->iaa_watchdog);
- port = HCS_N_PORTS (ehci->hcs_params);
spin_lock_irq (&ehci->lock);
+ /* Once the controller is stopped, port resumes that are already
+ * in progress won't complete. Hence if remote wakeup is enabled
+ * for the root hub and any ports are in the middle of a resume or
+ * 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;
+ }
+ }
+ }
+
/* stop schedules, clean any completed work */
if (HC_IS_RUNNING(hcd->state)) {
ehci_quiesce (ehci);
@@ -137,6 +154,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
*/
ehci->bus_suspended = 0;
ehci->owned_ports = 0;
+ port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
u32 __iomem *reg = &ehci->regs->port_status [port];
u32 t1 = ehci_readl(ehci, reg) & ~PORT_RWC_BITS;
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index 59bed3c4259d..dc25f4e59489 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -750,7 +750,20 @@ static int uhci_rh_suspend(struct usb_hcd *hcd)
spin_lock_irq(&uhci->lock);
if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
rc = -ESHUTDOWN;
- else if (!uhci->dead)
+ else if (uhci->dead)
+ ; /* Dead controllers tell no tales */
+
+ /* Once the controller is stopped, port resumes that are already
+ * in progress won't complete. Hence if remote wakeup is enabled
+ * for the root hub and any ports are in the middle of a resume or
+ * remote wakeup, we must fail the suspend.
+ */
+ else if (hcd->self.root_hub->do_remote_wakeup &&
+ uhci->resuming_ports) {
+ dev_dbg(uhci_dev(uhci), "suspend failed because a port "
+ "is resuming\n");
+ rc = -EBUSY;
+ } else
suspend_rh(uhci, UHCI_RH_SUSPENDED);
spin_unlock_irq(&uhci->lock);
return rc;