Merge branch 'master'; commit 'v2.6.38-rc7' into next

1 files changed, 22 insertions, 0 deletions

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 11446a1506da..a82e3756a72d 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -373,6 +373,27 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 			   (unsigned long)new_hw_ptr,
 			   (unsigned long)runtime->hw_ptr_base);
 	}
+
+	if (runtime->no_period_wakeup) {
+		/*
+		 * Without regular period interrupts, we have to check
+		 * the elapsed time to detect xruns.
+		 */
+		jdelta = jiffies - runtime->hw_ptr_jiffies;
+		if (jdelta < runtime->hw_ptr_buffer_jiffies / 2)
+			goto no_delta_check;
+		hdelta = jdelta - delta * HZ / runtime->rate;
+		while (hdelta > runtime->hw_ptr_buffer_jiffies / 2 + 1) {
+			delta += runtime->buffer_size;
+			hw_base += runtime->buffer_size;
+			if (hw_base >= runtime->boundary)
+				hw_base = 0;
+			new_hw_ptr = hw_base + pos;
+			hdelta -= runtime->hw_ptr_buffer_jiffies;
+		}
+		goto no_delta_check;
+	}
+
 	/* something must be really wrong */
 	if (delta >= runtime->buffer_size + runtime->period_size) {
 		hw_ptr_error(substream,
@@ -442,6 +463,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 			     (long)old_hw_ptr);
 	}
 
+ no_delta_check:
 	if (runtime->status->hw_ptr == new_hw_ptr)
 		return 0;