[svn-commits] sruffell: linux/trunk r7518 - /linux/trunk/drivers/dahdi/voicebus/

[SVN commits to the Digium repositories]

Author: sruffell
Date: Fri Nov  6 18:35:41 2009
New Revision: 7518

URL: http://svnview.digium.com/svn/dahdi?view=rev&rev=7518
Log:
voicebus: Add function to lock the latency.

Now that increases in the latency produce less undefined behavior on the SPI
busses, provide an interface for client drivers to inform the voicebus library
to not increase the latency if underruns are detected. This can speed up loads
of the driver since latency bumps do not trigger a restart of the driver
initialization. DAHDI-278.

Modified:
    linux/trunk/drivers/dahdi/voicebus/voicebus.c
    linux/trunk/drivers/dahdi/voicebus/voicebus.h

Modified: linux/trunk/drivers/dahdi/voicebus/voicebus.c
URL: http://svnview.digium.com/svn/dahdi/linux/trunk/drivers/dahdi/voicebus/voicebus.c?view=diff&rev=7518&r1=7517&r2=7518
==============================================================================
--- linux/trunk/drivers/dahdi/voicebus/voicebus.c (original)
+++ linux/trunk/drivers/dahdi/voicebus/voicebus.c Fri Nov  6 18:35:41 2009
@@ -234,6 +234,7 @@
 #define IN_DEFERRED_PROCESSING		3
 #define STOP				4
 #define STOPPED				5
+#define LATENCY_LOCKED			6
 
 #if VOICEBUS_DEFERRED == WORKQUEUE
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 18)
@@ -465,6 +466,36 @@
 	return latency;
 }
 EXPORT_SYMBOL(voicebus_current_latency);
+
+/**
+ * voicebus_lock_latency() - Do not increase the latency during underruns.
+ *
+ */
+void voicebus_lock_latency(struct voicebus *vb)
+{
+	set_bit(LATENCY_LOCKED, &vb->flags);
+}
+EXPORT_SYMBOL(voicebus_lock_latency);
+
+/**
+ * voicebus_unlock_latency() - Bump up the latency during underruns.
+ *
+ */
+void voicebus_unlock_latency(struct voicebus *vb)
+{
+	clear_bit(LATENCY_LOCKED, &vb->flags);
+}
+EXPORT_SYMBOL(voicebus_unlock_latency);
+
+/**
+ * voicebus_is_latency_locked() - Return 1 if latency is currently locked.
+ *
+ */
+int voicebus_is_latency_locked(const struct voicebus *vb)
+{
+	return test_bit(LATENCY_LOCKED, &vb->flags);
+}
+EXPORT_SYMBOL(voicebus_is_latency_locked);
 
 /*!
  * \brief Read one of the hardware control registers without acquiring locks.
@@ -1225,6 +1256,9 @@
 	if (0 == increase)
 		return;
 
+	if (test_bit(LATENCY_LOCKED, &vb->flags))
+		return;
+
 	if (unlikely(increase > VOICEBUS_MAXLATENCY_BUMP))
 		increase = VOICEBUS_MAXLATENCY_BUMP;
 
@@ -1385,7 +1419,6 @@
 	unsigned int i;
 	unsigned int idle_buffers;
 	int softunderrun;
-	unsigned int starting_latency;
 
 	int underrun = test_bit(TX_UNDERRUN, &vb->flags);
 
@@ -1448,7 +1481,6 @@
 	} else {
 		softunderrun = 0;
 		idle_buffers = 0;
-		starting_latency = 0;
 	}
 
 	/* Now we can process the completed non-idle buffers since we know at
@@ -1478,7 +1510,8 @@
 	 * descriptor ring. Otherwise it's possible to take so much time
 	 * printing the dmesg output that we lose the lead that we got on the
 	 * hardware, resulting in a hard underrun condition. */
-	if (unlikely(softunderrun) && printk_ratelimit()) {
+	if (unlikely(softunderrun &&
+	    !test_bit(LATENCY_LOCKED, &vb->flags) && printk_ratelimit())) {
 		if (vb->max_latency != vb->min_tx_buffer_count) {
 			dev_info(&vb->pdev->dev, "Missed interrupt. "
 				 "Increasing latency to %d ms in order to "

Modified: linux/trunk/drivers/dahdi/voicebus/voicebus.h
URL: http://svnview.digium.com/svn/dahdi/linux/trunk/drivers/dahdi/voicebus/voicebus.h?view=diff&rev=7518&r1=7517&r2=7518
==============================================================================
--- linux/trunk/drivers/dahdi/voicebus/voicebus.h (original)
+++ linux/trunk/drivers/dahdi/voicebus/voicebus.h Fri Nov  6 18:35:41 2009
@@ -58,6 +58,9 @@
 void voicebus_free(struct voicebus *vb, void *vbb);
 int voicebus_transmit(struct voicebus *vb, void *vbb);
 int voicebus_set_minlatency(struct voicebus *vb, unsigned int milliseconds);
-int voicebus_current_latency(struct voicebus *vb) ;
+int voicebus_current_latency(struct voicebus *vb);
+void voicebus_lock_latency(struct voicebus *vb);
+void voicebus_unlock_latency(struct voicebus *vb);
+int voicebus_is_latency_locked(const struct voicebus *vb);
  
 #endif /* __VOICEBUS_H__ */