[PATCH] USB UHCI: Use root-hub IRQs while suspended

This patch, which has as478b as a prerequisite, enables the uhci-hcd
driver to take advantage of root-hub IRQs rather than polling during the
time it is suspended.  (Unfortunately the hardware doesn't support
port-change interrupts while the controller is running.)  It also turns
off the driver's private timer while the controller is suspended, as it
isn't needed then.  The combined elimination of polling interrupts and
timer interrupts ought to be enough to allow some systems to save a
noticeable amount of power while they are otherwise idle.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index f5c75885f7be..77f264851e98 100644
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -32,6 +32,8 @@ static void uhci_free_pending_tds(struct uhci_hcd *uhci);
  */
 static inline void uhci_set_next_interrupt(struct uhci_hcd *uhci)
 {
+        if (uhci->is_stopped)
+                mod_timer(&uhci->stall_timer, jiffies);
         uhci->term_td->status |= cpu_to_le32(TD_CTRL_IOC); 
 }
 
@@ -1497,6 +1499,7 @@ static void uhci_scan_schedule(struct uhci_hcd *uhci, struct pt_regs *regs)
  rescan:
         uhci->need_rescan = 0;
 
+        uhci_clear_next_interrupt(uhci);
         uhci_get_current_frame_number(uhci);
 
         if (uhci->frame_number + uhci->is_stopped != uhci->qh_remove_age)