ALSA: pcm: optimize xrun detection in no-period-wakeup mode
[linux-2.6.git] / sound / core / pcm_lib.c
index e9debaa..fd18c3c 100644 (file)
@@ -380,6 +380,8 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
                 * 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;