USB: EHCI: add separate IAA watchdog timer

This patch (as1028) was mostly written by David Brownell; I made only
a few changes (extra log info and a small bug fix -- which might
account for why David's version had to be reverted).  It adds a new
watchdog timer to the ehci-hcd driver to be used exclusively for
detecting lost or missing IAA notifications.

Previously a shared timer had been used, which may have led to some
problems as reported by Christian Hoffmann.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 7 deletions

diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 10e71417c352..eeda4c88ebae 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -74,7 +74,6 @@ struct ehci_hcd {			/* one per controller */
         /* async schedule support */
         struct ehci_qh          *async;
         struct ehci_qh          *reclaim;
-        unsigned                reclaim_ready : 1;
         unsigned                scanning : 1;
 
         /* periodic schedule support */
@@ -105,6 +104,7 @@ struct ehci_hcd {			/* one per controller */
         struct dma_pool         *itd_pool;      /* itd per iso urb */
         struct dma_pool         *sitd_pool;     /* sitd per split iso urb */
 
+        struct timer_list       iaa_watchdog;
         struct timer_list       watchdog;
         unsigned long           actions;
         unsigned                stamp;
@@ -148,9 +148,21 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci)
 }
 
 
+static inline void
+iaa_watchdog_start(struct ehci_hcd *ehci)
+{
+        WARN_ON(timer_pending(&ehci->iaa_watchdog));
+        mod_timer(&ehci->iaa_watchdog,
+                        jiffies + msecs_to_jiffies(EHCI_IAA_MSECS));
+}
+
+static inline void iaa_watchdog_done(struct ehci_hcd *ehci)
+{
+        del_timer(&ehci->iaa_watchdog);
+}
+
 enum ehci_timer_action {
         TIMER_IO_WATCHDOG,
-        TIMER_IAA_WATCHDOG,
         TIMER_ASYNC_SHRINK,
         TIMER_ASYNC_OFF,
 };
@@ -168,9 +180,6 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
                 unsigned long t;
 
                 switch (action) {
-                case TIMER_IAA_WATCHDOG:
-                        t = EHCI_IAA_JIFFIES;
-                        break;
                 case TIMER_IO_WATCHDOG:
                         t = EHCI_IO_JIFFIES;
                         break;
@@ -187,8 +196,7 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
                 // async queue SHRINK often precedes IAA.  while it's ready
                 // to go OFF neither can matter, and afterwards the IO
                 // watchdog stops unless there's still periodic traffic.
-                if (action != TIMER_IAA_WATCHDOG
-                                && t > ehci->watchdog.expires
+                if (time_before_eq(t, ehci->watchdog.expires)
                                 && timer_pending (&ehci->watchdog))
                         return;
                 mod_timer (&ehci->watchdog, t);