ALSA: Rewrite hw_ptr updaters

Clean up and improve snd_pcm_update_hw_ptr*() functions.

snd_pcm_update_hw_ptr() tries to detect the unexpected hwptr jumps
more strictly to avoid the position mess-up, which often results in
the bad quality I/O with pulseaudio.

The hw-ptr skip error messages are printed when xrun proc is set to
non-zero.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 921691080f35ff8301301507b9259ae9c89d400f..86ac9ae9460e6210d7f444c0484c14383cb01bf9 100644 (file)
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -125,19 +125,27 @@ void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_ufram
        }
 }
 
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+#define xrun_debug(substream)  ((substream)->pstr->xrun_debug)
+#else
+#define xrun_debug(substream)  0
+#endif
+
+#define dump_stack_on_xrun(substream) do {     \
+               if (xrun_debug(substream) > 1)  \
+                       dump_stack();           \
+       } while (0)
+
 static void xrun(struct snd_pcm_substream *substream)
 {
        snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
-#ifdef CONFIG_SND_PCM_XRUN_DEBUG
-       if (substream->pstr->xrun_debug) {
+       if (xrun_debug(substream)) {
                snd_printd(KERN_DEBUG "XRUN: pcmC%dD%d%c\n",
                           substream->pcm->card->number,
                           substream->pcm->device,
                           substream->stream ? 'c' : 'p');
-               if (substream->pstr->xrun_debug > 1)
-                       dump_stack();
+               dump_stack_on_xrun(substream);
        }
-#endif
 }
 
 static inline snd_pcm_uframes_t snd_pcm_update_hw_ptr_pos(struct snd_pcm_substream *substream,
@@ -182,11 +190,21 @@ static inline int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream
        return 0;
 }
 
+#define hw_ptr_error(substream, fmt, args...)                          \
+       do {                                                            \
+               if (xrun_debug(substream)) {                            \
+                       if (printk_ratelimit()) {                       \
+                               snd_printd("hda_codec: " fmt, ##args);  \
+                       }                                               \
+                       dump_stack_on_xrun(substream);                  \
+               }                                                       \
+       } while (0)
+
 static inline 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;
+       snd_pcm_uframes_t new_hw_ptr, hw_ptr_interrupt, hw_base;
        snd_pcm_sframes_t delta;
 
        pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
@@ -194,36 +212,47 @@ static inline int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *subs
                xrun(substream);
                return -EPIPE;
        }
-       if (runtime->period_size == runtime->buffer_size)
-               goto __next_buf;
-       new_hw_ptr = runtime->hw_ptr_base + pos;
+       hw_base = runtime->hw_ptr_base;
+       new_hw_ptr = hw_base + pos;
        hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
-
-       delta = hw_ptr_interrupt - new_hw_ptr;
-       if (delta > 0) {
-               if ((snd_pcm_uframes_t)delta < runtime->buffer_size / 2) {
-#ifdef CONFIG_SND_PCM_XRUN_DEBUG
-                       if (runtime->periods > 1 && substream->pstr->xrun_debug) {
-                               snd_printd(KERN_ERR "Unexpected hw_pointer value [1] (stream = %i, delta: -%ld, max jitter = %ld): wrong interrupt acknowledge?\n", substream->stream, (long) delta, runtime->buffer_size / 2);
-                               if (substream->pstr->xrun_debug > 1)
-                                       dump_stack();
-                       }
-#endif
-                       return 0;
+       delta = new_hw_ptr - hw_ptr_interrupt;
+       if (hw_ptr_interrupt == runtime->boundary)
+               hw_ptr_interrupt = 0;
+       if (delta < 0) {
+               delta += runtime->buffer_size;
+               if (delta < 0) {
+                       hw_ptr_error(substream, 
+                                    "Unexpected hw_pointer value "
+                                    "(stream=%i, pos=%ld, intr_ptr=%ld)\n",
+                                    substream->stream, (long)pos,
+                                    (long)hw_ptr_interrupt);
+                       /* rebase to interrupt position */
+                       hw_base = new_hw_ptr = hw_ptr_interrupt;
+                       delta = 0;
+               } else {
+                       hw_base += runtime->buffer_size;
+                       if (hw_base == runtime->boundary)
+                               hw_base = 0;
+                       new_hw_ptr = hw_base + pos;
                }
-             __next_buf:
-               runtime->hw_ptr_base += runtime->buffer_size;
-               if (runtime->hw_ptr_base == runtime->boundary)
-                       runtime->hw_ptr_base = 0;
-               new_hw_ptr = runtime->hw_ptr_base + pos;
        }
-
+       if (delta > runtime->period_size) {
+               hw_ptr_error(substream,
+                            "Lost interrupts? "
+                            "(stream=%i, delta=%ld, intr_ptr=%ld)\n",
+                            substream->stream, (long)delta,
+                            (long)hw_ptr_interrupt);
+               /* rebase hw_ptr_interrupt */
+               hw_ptr_interrupt =
+                       new_hw_ptr - new_hw_ptr % runtime->period_size;
+       }
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
            runtime->silence_size > 0)
                snd_pcm_playback_silence(substream, new_hw_ptr);
 
+       runtime->hw_ptr_base = hw_base;
        runtime->status->hw_ptr = new_hw_ptr;
-       runtime->hw_ptr_interrupt = new_hw_ptr - new_hw_ptr % runtime->period_size;
+       runtime->hw_ptr_interrupt = hw_ptr_interrupt;
 
        return snd_pcm_update_hw_ptr_post(substream, runtime);
 }
@@ -233,7 +262,7 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        snd_pcm_uframes_t pos;
-       snd_pcm_uframes_t old_hw_ptr, new_hw_ptr;
+       snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_base;
        snd_pcm_sframes_t delta;
 
        old_hw_ptr = runtime->status->hw_ptr;
@@ -242,29 +271,38 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
                xrun(substream);
                return -EPIPE;
        }
-       new_hw_ptr = runtime->hw_ptr_base + pos;
-
-       delta = old_hw_ptr - new_hw_ptr;
-       if (delta > 0) {
-               if ((snd_pcm_uframes_t)delta < runtime->buffer_size / 2) {
-#ifdef CONFIG_SND_PCM_XRUN_DEBUG
-                       if (runtime->periods > 2 && substream->pstr->xrun_debug) {
-                               snd_printd(KERN_ERR "Unexpected hw_pointer value [2] (stream = %i, delta: -%ld, max jitter = %ld): wrong interrupt acknowledge?\n", substream->stream, (long) delta, runtime->buffer_size / 2);
-                               if (substream->pstr->xrun_debug > 1)
-                                       dump_stack();
-                       }
-#endif
+       hw_base = runtime->hw_ptr_base;
+       new_hw_ptr = hw_base + pos;
+
+       delta = new_hw_ptr - old_hw_ptr;
+       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",
+                                    substream->stream, (long)pos,
+                                    (long)old_hw_ptr);
                        return 0;
                }
-               runtime->hw_ptr_base += runtime->buffer_size;
-               if (runtime->hw_ptr_base == runtime->boundary)
-                       runtime->hw_ptr_base = 0;
-               new_hw_ptr = runtime->hw_ptr_base + pos;
+               hw_base += runtime->buffer_size;
+               if (hw_base == runtime->boundary)
+                       hw_base = 0;
+               new_hw_ptr = hw_base + pos;
+       }
+       if (delta > runtime->period_size && runtime->periods > 1) {
+               hw_ptr_error(substream,
+                            "hw_ptr skipping! "
+                            "(pos=%ld, delta=%ld, period=%ld)\n",
+                            (long)pos, (long)delta,
+                            (long)runtime->period_size);
+               return 0;
        }
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
            runtime->silence_size > 0)
                snd_pcm_playback_silence(substream, new_hw_ptr);
 
+       runtime->hw_ptr_base = hw_base;
        runtime->status->hw_ptr = new_hw_ptr;
 
        return snd_pcm_update_hw_ptr_post(substream, runtime);