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ALSA: pcm: Add xrun_injection proc entry

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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>
This commit is contained in:
Takashi Iwai 2014-11-04 14:02:40 +01:00
parent f5914908a5
commit 2b30d411db
3 changed files with 40 additions and 0 deletions
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4
Documentation/sound/alsa/Procfile.txt
View file

@ -133,6 +133,10 @@ card*/pcm*/sub*/sw_params
card*/pcm*/sub*/prealloc
The buffer pre-allocation information.
card*/pcm*/sub*/xrun_injection
Triggers an XRUN to the running stream when any value is
written to this proc file. Used for fault injection.
This entry is write-only.
AC97 Codec Information
----------------------

3
include/sound/pcm.h
View file

@ -416,7 +416,10 @@ struct snd_pcm_substream {
struct snd_info_entry *proc_status_entry;
struct snd_info_entry *proc_prealloc_entry;
struct snd_info_entry *proc_prealloc_max_entry;
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
struct snd_info_entry *proc_xrun_injection_entry;
#endif
#endif /* CONFIG_SND_VERBOSE_PROCFS */
/* misc flags */
unsigned int hw_opened: 1;
};

33
sound/core/pcm.c
View file

@ -483,6 +483,19 @@ static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
}
#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 @@ static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
}
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 @@ static int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream)
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;