5 files changed, 59 insertions, 42 deletions

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 86e8ee169c67..74ffd20edff8 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -94,8 +94,6 @@ static const char	hcd_name [] = "ehci_hcd";
 #define EHCI_TUNE_FLS           1       /* (medium) 512-frame schedule */
 
 #define EHCI_IO_JIFFIES         (HZ/10)         /* io watchdog > irq_thresh */
-#define EHCI_SHRINK_JIFFIES     (DIV_ROUND_UP(HZ, 200) + 1)
-                                                /* 5-ms async qh unlink delay */
 
 /* Initial IRQ latency:  faster than hw default */
 static int log2_irq_thresh = 0;         // 0 to 6
@@ -130,15 +128,6 @@ MODULE_PARM_DESC(hird, "host initiated resume duration, +1 for each 75us");
 static void
 timer_action(struct ehci_hcd *ehci, enum ehci_timer_action action)
 {
-        /* Don't override timeouts which shrink or (later) disable
-         * the async ring; just the I/O watchdog.  Note that if a
-         * SHRINK were pending, OFF would never be requested.
-         */
-        if (timer_pending(&ehci->watchdog)
-                        && (BIT(TIMER_ASYNC_SHRINK)
-                                & ehci->actions))
-                return;
-
         if (!test_and_set_bit(action, &ehci->actions)) {
                 unsigned long t;
 
@@ -148,10 +137,6 @@ timer_action(struct ehci_hcd *ehci, enum ehci_timer_action action)
                                 return;
                         t = EHCI_IO_JIFFIES;
                         break;
-                /* case TIMER_ASYNC_SHRINK: */
-                default:
-                        t = EHCI_SHRINK_JIFFIES;
-                        break;
                 }
                 mod_timer(&ehci->watchdog, t + jiffies);
         }
@@ -307,6 +292,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
 /*-------------------------------------------------------------------------*/
 
 static void end_unlink_async(struct ehci_hcd *ehci);
+static void unlink_empty_async(struct ehci_hcd *ehci);
 static void ehci_work(struct ehci_hcd *ehci);
 static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh);
 static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh);
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index a3822700e496..5d84562e2716 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -300,6 +300,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
         ehci->rh_state = EHCI_RH_SUSPENDED;
 
         end_unlink_async(ehci);
+        unlink_empty_async(ehci);
         ehci_handle_intr_unlinks(ehci);
         end_free_itds(ehci);
 
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 181832921c53..bae931767825 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1205,7 +1205,7 @@ static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested)
                         end_unlink_async(ehci);
 
         /* Otherwise start a new IAA cycle */
-        } else {
+        } else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) {
                 /* Make sure the unlinks are all visible to the hardware */
                 wmb();
 
@@ -1253,6 +1253,39 @@ static void end_unlink_async(struct ehci_hcd *ehci)
         }
 }
 
+static void unlink_empty_async(struct ehci_hcd *ehci)
+{
+        struct ehci_qh          *qh, *next;
+        bool                    stopped = (ehci->rh_state < EHCI_RH_RUNNING);
+        bool                    check_unlinks_later = false;
+
+        /* Unlink all the async QHs that have been empty for a timer cycle */
+        next = ehci->async->qh_next.qh;
+        while (next) {
+                qh = next;
+                next = qh->qh_next.qh;
+
+                if (list_empty(&qh->qtd_list) &&
+                                qh->qh_state == QH_STATE_LINKED) {
+                        if (!stopped && qh->unlink_cycle ==
+                                        ehci->async_unlink_cycle)
+                                check_unlinks_later = true;
+                        else
+                                single_unlink_async(ehci, qh);
+                }
+        }
+
+        /* Start a new IAA cycle if any QHs are waiting for it */
+        if (ehci->async_unlink)
+                start_iaa_cycle(ehci, false);
+
+        /* QHs that haven't been empty for long enough will be handled later */
+        if (check_unlinks_later) {
+                ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
+                ++ehci->async_unlink_cycle;
+        }
+}
+
 /* makes sure the async qh will become idle */
 /* caller must own ehci->lock */
 
@@ -1277,12 +1310,8 @@ static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
 
 static void scan_async (struct ehci_hcd *ehci)
 {
-        bool                    stopped;
         struct ehci_qh          *qh;
-        enum ehci_timer_action  action = TIMER_IO_WATCHDOG;
-
-        timer_action_done (ehci, TIMER_ASYNC_SHRINK);
-        stopped = (ehci->rh_state < EHCI_RH_RUNNING);
+        bool                    check_unlinks_later = false;
 
         ehci->qh_scan_next = ehci->async->qh_next.qh;
         while (ehci->qh_scan_next) {
@@ -1301,28 +1330,27 @@ static void scan_async (struct ehci_hcd *ehci)
                          * in single_unlink_async().
                          */
                         temp = qh_completions(ehci, qh);
-                        if (qh->needs_rescan)
+                        if (qh->needs_rescan) {
                                 start_unlink_async(ehci, qh);
-                        qh->unlink_time = jiffies + EHCI_SHRINK_JIFFIES;
-                        if (temp != 0)
+                        } else if (list_empty(&qh->qtd_list)
+                                        && qh->qh_state == QH_STATE_LINKED) {
+                                qh->unlink_cycle = ehci->async_unlink_cycle;
+                                check_unlinks_later = true;
+                        } else if (temp != 0)
                                 goto rescan;
                 }
+        }
 
-                /* unlink idle entries, reducing DMA usage as well
-                 * as HCD schedule-scanning costs.  delay for any qh
-                 * we just scanned, there's a not-unusual case that it
-                 * doesn't stay idle for long.
-                 * (plus, avoids some kind of re-activation race.)
-                 */
-                if (list_empty(&qh->qtd_list)
-                                && qh->qh_state == QH_STATE_LINKED) {
-                        if (!ehci->async_unlink && (stopped ||
-                                        time_after_eq(jiffies, qh->unlink_time)))
-                                start_unlink_async(ehci, qh);
-                        else
-                                action = TIMER_ASYNC_SHRINK;
-                }
+        /*
+         * Unlink empty entries, reducing DMA usage as well
+         * as HCD schedule-scanning costs.  Delay for any qh
+         * we just scanned, there's a not-unusual case that it
+         * doesn't stay idle for long.
+         */
+        if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING &&
+                        !(ehci->enabled_hrtimer_events &
+                                BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) {
+                ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
+                ++ehci->async_unlink_cycle;
         }
-        if (action == TIMER_ASYNC_SHRINK)
-                timer_action (ehci, TIMER_ASYNC_SHRINK);
 }
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
index 8ca5f152f5bd..a823290b5139 100644
--- a/drivers/usb/host/ehci-timer.c
+++ b/drivers/usb/host/ehci-timer.c
@@ -72,6 +72,7 @@ static unsigned event_delays_ns[] = {
         1 * NSEC_PER_MSEC,      /* EHCI_HRTIMER_POLL_DEAD */
         1125 * NSEC_PER_USEC,   /* EHCI_HRTIMER_UNLINK_INTR */
         2 * NSEC_PER_MSEC,      /* EHCI_HRTIMER_FREE_ITDS */
+        6 * NSEC_PER_MSEC,      /* EHCI_HRTIMER_ASYNC_UNLINKS */
         10 * NSEC_PER_MSEC,     /* EHCI_HRTIMER_IAA_WATCHDOG */
         10 * NSEC_PER_MSEC,     /* EHCI_HRTIMER_DISABLE_PERIODIC */
         15 * NSEC_PER_MSEC,     /* EHCI_HRTIMER_DISABLE_ASYNC */
@@ -347,6 +348,7 @@ static void (*event_handlers[])(struct ehci_hcd *) = {
         ehci_handle_controller_death,   /* EHCI_HRTIMER_POLL_DEAD */
         ehci_handle_intr_unlinks,       /* EHCI_HRTIMER_UNLINK_INTR */
         end_free_itds,                  /* EHCI_HRTIMER_FREE_ITDS */
+        unlink_empty_async,             /* EHCI_HRTIMER_ASYNC_UNLINKS */
         ehci_iaa_watchdog,              /* EHCI_HRTIMER_IAA_WATCHDOG */
         ehci_disable_PSE,               /* EHCI_HRTIMER_DISABLE_PERIODIC */
         ehci_disable_ASE,               /* EHCI_HRTIMER_DISABLE_ASYNC */
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 1a782775881b..303c36cc99c9 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -84,6 +84,7 @@ enum ehci_hrtimer_event {
         EHCI_HRTIMER_POLL_DEAD,         /* Wait for dead controller to stop */
         EHCI_HRTIMER_UNLINK_INTR,       /* Wait for interrupt QH unlink */
         EHCI_HRTIMER_FREE_ITDS,         /* Wait for unused iTDs and siTDs */
+        EHCI_HRTIMER_ASYNC_UNLINKS,     /* Unlink empty async QHs */
         EHCI_HRTIMER_IAA_WATCHDOG,      /* Handle lost IAA interrupts */
         EHCI_HRTIMER_DISABLE_PERIODIC,  /* Wait to disable periodic sched */
         EHCI_HRTIMER_DISABLE_ASYNC,     /* Wait to disable async sched */
@@ -123,6 +124,7 @@ struct ehci_hcd {			/* one per controller */
         struct ehci_qh          *async_unlink_last;
         struct ehci_qh          *async_iaa;
         struct ehci_qh          *qh_scan_next;
+        unsigned                async_unlink_cycle;
         unsigned                async_count;    /* async activity count */
 
         /* periodic schedule support */
@@ -232,7 +234,6 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci)
 
 enum ehci_timer_action {
         TIMER_IO_WATCHDOG,
-        TIMER_ASYNC_SHRINK,
 };
 
 static inline void
@@ -382,7 +383,6 @@ struct ehci_qh {
         struct ehci_qtd         *dummy;
         struct ehci_qh          *unlink_next;   /* next on unlink list */
 
-        unsigned long           unlink_time;
         unsigned                unlink_cycle;
         unsigned                stamp;