ALSA: aloop: Fix random zeros in capture data when using jiffies timer

In loopback_jiffies_timer_pos_update(), we are getting jiffies twice.
First time for playback, second time for capture. Jiffies can be updated
between these two calls and if the capture jiffies is larger, extra zeros
will be filled in the capture buffer.

Change to get jiffies once and use it for both playback and capture.

Signed-off-by: Pattara Teerapong <pteerapong@chromium.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220901144036.4049060-1-pteerapong@chromium.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index 9b4a7cd..12f12a2 100644 (file)
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -605,17 +605,18 @@ static unsigned int loopback_jiffies_timer_pos_update
                        cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
        struct loopback_pcm *dpcm_capt =
                        cable->streams[SNDRV_PCM_STREAM_CAPTURE];
-       unsigned long delta_play = 0, delta_capt = 0;
+       unsigned long delta_play = 0, delta_capt = 0, cur_jiffies;
        unsigned int running, count1, count2;
 
+       cur_jiffies = jiffies;
        running = cable->running ^ cable->pause;
        if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
-               delta_play = jiffies - dpcm_play->last_jiffies;
+               delta_play = cur_jiffies - dpcm_play->last_jiffies;
                dpcm_play->last_jiffies += delta_play;
        }
 
        if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
-               delta_capt = jiffies - dpcm_capt->last_jiffies;
+               delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
                dpcm_capt->last_jiffies += delta_capt;
        }