ALSA: pcm: Add xrun_injection proc entry
This patch adds a new proc entry for PCM substreams to inject an
XRUN. When a PCM substream is running and any value is written to its
xrun_injection proc file, the driver triggers XRUN. This is a useful
feature for debugging XRUN and error handling code paths.
Note that this entry is enabled only when CONFIG_SND_PCM_XRUN_DEBUG is
set.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 31acc3d..8f624b7 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -483,6 +483,19 @@
}
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+static void snd_pcm_xrun_injection_write(struct snd_info_entry *entry,
+ struct snd_info_buffer *buffer)
+{
+ struct snd_pcm_substream *substream = entry->private_data;
+ struct snd_pcm_runtime *runtime;
+
+ snd_pcm_stream_lock_irq(substream);
+ runtime = substream->runtime;
+ if (runtime && runtime->status->state == SNDRV_PCM_STATE_RUNNING)
+ snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+ snd_pcm_stream_unlock_irq(substream);
+}
+
static void snd_pcm_xrun_debug_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
@@ -614,6 +627,22 @@
}
substream->proc_status_entry = entry;
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+ entry = snd_info_create_card_entry(card, "xrun_injection",
+ substream->proc_root);
+ if (entry) {
+ entry->private_data = substream;
+ entry->c.text.read = NULL;
+ entry->c.text.write = snd_pcm_xrun_injection_write;
+ entry->mode = S_IFREG | S_IWUSR;
+ if (snd_info_register(entry) < 0) {
+ snd_info_free_entry(entry);
+ entry = NULL;
+ }
+ }
+ substream->proc_xrun_injection_entry = entry;
+#endif /* CONFIG_SND_PCM_XRUN_DEBUG */
+
return 0;
}
@@ -627,6 +656,10 @@
substream->proc_sw_params_entry = NULL;
snd_info_free_entry(substream->proc_status_entry);
substream->proc_status_entry = NULL;
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+ snd_info_free_entry(substream->proc_xrun_injection_entry);
+ substream->proc_xrun_injection_entry = NULL;
+#endif
snd_info_free_entry(substream->proc_root);
substream->proc_root = NULL;
return 0;