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authorAlan Stern <stern@rowland.harvard.edu>2010-01-08 11:18:20 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-01-20 15:24:34 -0800
commitcec3a53c7fe794237b582e8e77fc0e48465e65ee (patch)
treebc73dbdef0688d6c656d04f288e736cb9b60d9b9
parent1b9a38bfa6e664ff02511314f5586d711c83cc91 (diff)
downloadlinux-stericsson-cec3a53c7fe794237b582e8e77fc0e48465e65ee.tar.gz
USB: EHCI & UHCI: fix race between root-hub suspend and port resume
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> Cc: stable <stable@kernel.org> 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 2c6571c05f35..c75d9270c752 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -120,9 +120,26 @@ 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);
@@ -138,6 +155,7 @@ 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 5cd0e48f67fb..99cd00fd3514 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -749,7 +749,20 @@ 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;