ALSA: sound, core, pcm_lib: xrun_log: log also in_interrupt
Ben Gardiner [Wed, 18 May 2011 14:03:34 +0000 (10:03 -0400)]
When debugging pcm drivers I found the "period" or "hw" prefix printed
by either XRUN_DEBUG_PERIODUPDATE or XRUN_DEBUG_PERIODUPDATE events,
respectively to be very useful is observing the interplay between
interrupt-context updates and syscall-context updates.

Similarly, when debugging overruns with XRUN_DEBUG_LOG it is useful to
see the context of the last 10 positions.

Add an in_interrupt member to hwptr_log_entry which stores the value of
the in_interrupt parameter of snd_pcm_update_hw_ptr0 when the log entry
is created. Print a "[Q]" prefix when dumping the log entries if
in_interrupt was true.

Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm_lib.c

index 64449cb..c8c8091 100644 (file)
@@ -189,6 +189,7 @@ static void xrun(struct snd_pcm_substream *substream)
 #define XRUN_LOG_CNT   10
 
 struct hwptr_log_entry {
+       unsigned int in_interrupt;
        unsigned long jiffies;
        snd_pcm_uframes_t pos;
        snd_pcm_uframes_t period_size;
@@ -204,7 +205,7 @@ struct snd_pcm_hwptr_log {
 };
 
 static void xrun_log(struct snd_pcm_substream *substream,
-                    snd_pcm_uframes_t pos)
+                    snd_pcm_uframes_t pos, int in_interrupt)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_pcm_hwptr_log *log = runtime->hwptr_log;
@@ -220,6 +221,7 @@ static void xrun_log(struct snd_pcm_substream *substream,
                        return;
        }
        entry = &log->entries[log->idx];
+       entry->in_interrupt = in_interrupt;
        entry->jiffies = jiffies;
        entry->pos = pos;
        entry->period_size = runtime->period_size;
@@ -246,9 +248,11 @@ static void xrun_log_show(struct snd_pcm_substream *substream)
                entry = &log->entries[idx];
                if (entry->period_size == 0)
                        break;
-               snd_printd("hwptr log: %s: j=%lu, pos=%ld/%ld/%ld, "
+               snd_printd("hwptr log: %s: %sj=%lu, pos=%ld/%ld/%ld, "
                           "hwptr=%ld/%ld\n",
-                          name, entry->jiffies, (unsigned long)entry->pos,
+                          name, entry->in_interrupt ? "[Q] " : "",
+                          entry->jiffies,
+                          (unsigned long)entry->pos,
                           (unsigned long)entry->period_size,
                           (unsigned long)entry->buffer_size,
                           (unsigned long)entry->old_hw_ptr,
@@ -326,7 +330,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
        }
        pos -= pos % runtime->min_align;
        if (xrun_debug(substream, XRUN_DEBUG_LOG))
-               xrun_log(substream, pos);
+               xrun_log(substream, pos, in_interrupt);
        hw_base = runtime->hw_ptr_base;
        new_hw_ptr = hw_base + pos;
        if (in_interrupt) {