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| author | Takashi Iwai <tiwai@suse.de> | 2017-06-13 15:57:28 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2017-06-14 07:44:27 +0200 |
| commit | f8ff2f28ba49fa41a06215ac3187dede347bc9a7 (patch) | |
| tree | 7e6c9f57461f824acf91fe45b0f4b2166e9f8c0d /sound/core | |
| parent | ALSA: pcm: Use common PCM_RUNTIME_CHECK() for sanity checks (diff) | |
| download | linux-f8ff2f28ba49fa41a06215ac3187dede347bc9a7.tar.xz linux-f8ff2f28ba49fa41a06215ac3187dede347bc9a7.zip | |
ALSA: pcm: Skip ack callback without actual appl_ptr update
We call ack callback whenever appl_ptr gets updated via
pcm_lib_apply_appl_ptr(). There are various code paths to call this
function. A part of them are for read/write/forward/rewind, where the
appl_ptr is always changed and thus the call of ack is mandatory.
OTOH, another part of code paths are from the explicit user call,
e.g. via SYNC_PTR ioctl. There, we may receive the same appl_ptr
value, and in such a case, calling ack is obviously superfluous.
This patch adds the check of the given appl_ptr value, and returns
immediately if it's no real update.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/pcm_lib.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index e73b6e4135f6..75308ddc54ca 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -2112,6 +2112,9 @@ int pcm_lib_apply_appl_ptr(struct snd_pcm_substream *substream, snd_pcm_uframes_t old_appl_ptr = runtime->control->appl_ptr; int ret; + if (old_appl_ptr == appl_ptr) + return 0; + runtime->control->appl_ptr = appl_ptr; if (substream->ops->ack) { ret = substream->ops->ack(substream); |