---

yaml
---
r: 317031
b: refs/heads/master
c: 32830f2
h: refs/heads/master
i:
  317029: f5e7969
  317027: f08d84a
  317023: f38674a
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3c273a056bf46167f0a1309c2ba72282a17d2541
+refs/heads/master: 32830f207691176234b4c4dd17f0d7ab6d87d94b

trunk/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);

trunk/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);
 

trunk/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);
 }

trunk/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 */

trunk/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;