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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 /drivers/usb/host/ehci-hub.c
parent1b9a38bfa6e664ff02511314f5586d711c83cc91 (diff)
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>
Diffstat (limited to 'drivers/usb/host/ehci-hub.c')
-rw-r--r--drivers/usb/host/ehci-hub.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 2c6571c05f3..c75d9270c75 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;