2 files changed, 41 insertions, 9 deletions

diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 8904b1900d7f..c17296891617 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -268,7 +268,8 @@ struct snd_pcm_runtime {
         int overrange;
         snd_pcm_uframes_t avail_max;
         snd_pcm_uframes_t hw_ptr_base;  /* Position at buffer restart */
-        snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time*/
+        snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time */
+        unsigned long hw_ptr_jiffies;   /* Time when hw_ptr is updated */
 
         /* -- HW params -- */
         snd_pcm_access_t access;        /* access mode */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index fbb2e391591e..63d088f2265f 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -209,9 +209,11 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
 {
         struct snd_pcm_runtime *runtime = substream->runtime;
         snd_pcm_uframes_t pos;
-        snd_pcm_uframes_t new_hw_ptr, hw_ptr_interrupt, hw_base;
-        snd_pcm_sframes_t delta;
+        snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_ptr_interrupt, hw_base;
+        snd_pcm_sframes_t hdelta, delta;
+        unsigned long jdelta;
 
+        old_hw_ptr = runtime->status->hw_ptr;
         pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
         if (pos == SNDRV_PCM_POS_XRUN) {
                 xrun(substream);
@@ -247,7 +249,30 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
                         new_hw_ptr = hw_base + pos;
                 }
         }
-        if (delta > runtime->period_size) {
+        hdelta = new_hw_ptr - old_hw_ptr;
+        jdelta = jiffies - runtime->hw_ptr_jiffies;
+        if (((hdelta * HZ) / runtime->rate) > jdelta + HZ/100) {
+                delta = jdelta /
+                        (((runtime->period_size * HZ) / runtime->rate)
+                                                                + HZ/100);
+                hw_ptr_error(substream,
+                             "hw_ptr skipping! [Q] "
+                             "(pos=%ld, delta=%ld, period=%ld, "
+                             "jdelta=%lu/%lu/%lu)\n",
+                             (long)pos, (long)hdelta,
+                             (long)runtime->period_size, jdelta,
+                             ((hdelta * HZ) / runtime->rate), delta);
+                hw_ptr_interrupt = runtime->hw_ptr_interrupt +
+                                   runtime->period_size * delta;
+                if (hw_ptr_interrupt >= runtime->boundary)
+                        hw_ptr_interrupt -= runtime->boundary;
+                /* rebase to interrupt position */
+                hw_base = new_hw_ptr = hw_ptr_interrupt;
+                /* align hw_base to buffer_size */
+                hw_base -= hw_base % runtime->buffer_size;
+                delta = 0;
+        }
+        if (delta > runtime->period_size + runtime->period_size / 2) {
                 hw_ptr_error(substream,
                              "Lost interrupts? "
                              "(stream=%i, delta=%ld, intr_ptr=%ld)\n",
@@ -263,6 +288,7 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
 
         runtime->hw_ptr_base = hw_base;
         runtime->status->hw_ptr = new_hw_ptr;
+        runtime->hw_ptr_jiffies = jiffies;
         runtime->hw_ptr_interrupt = hw_ptr_interrupt;
 
         return snd_pcm_update_hw_ptr_post(substream, runtime);
@@ -275,6 +301,7 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
         snd_pcm_uframes_t pos;
         snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_base;
         snd_pcm_sframes_t delta;
+        unsigned long jdelta;
 
         old_hw_ptr = runtime->status->hw_ptr;
         pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
@@ -286,14 +313,15 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
         new_hw_ptr = hw_base + pos;
 
         delta = new_hw_ptr - old_hw_ptr;
+        jdelta = jiffies - runtime->hw_ptr_jiffies;
         if (delta < 0) {
                 delta += runtime->buffer_size;
                 if (delta < 0) {
                         hw_ptr_error(substream, 
                                      "Unexpected hw_pointer value [2] "
-                                     "(stream=%i, pos=%ld, old_ptr=%ld)\n",
+                                     "(stream=%i, pos=%ld, old_ptr=%ld, jdelta=%li)\n",
                                      substream->stream, (long)pos,
-                                     (long)old_hw_ptr);
+                                     (long)old_hw_ptr, jdelta);
                         return 0;
                 }
                 hw_base += runtime->buffer_size;
@@ -301,12 +329,13 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
                         hw_base = 0;
                 new_hw_ptr = hw_base + pos;
         }
-        if (delta > runtime->period_size && runtime->periods > 1) {
+        if (((delta * HZ) / runtime->rate) > jdelta + HZ/100) {
                 hw_ptr_error(substream,
                              "hw_ptr skipping! "
-                             "(pos=%ld, delta=%ld, period=%ld)\n",
+                             "(pos=%ld, delta=%ld, period=%ld, jdelta=%lu/%lu)\n",
                              (long)pos, (long)delta,
-                             (long)runtime->period_size);
+                             (long)runtime->period_size, jdelta,
+                             ((delta * HZ) / runtime->rate));
                 return 0;
         }
         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
@@ -315,6 +344,7 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
 
         runtime->hw_ptr_base = hw_base;
         runtime->status->hw_ptr = new_hw_ptr;
+        runtime->hw_ptr_jiffies = jiffies;
 
         return snd_pcm_update_hw_ptr_post(substream, runtime);
 }
@@ -1441,6 +1471,7 @@ static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
                 runtime->status->hw_ptr %= runtime->buffer_size;
         else
                 runtime->status->hw_ptr = 0;
+        runtime->hw_ptr_jiffies = jiffies;
         snd_pcm_stream_unlock_irqrestore(substream, flags);
         return 0;
 }