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-rw-r--r--drivers/media/usb/em28xx/em28xx-audio.c8
-rw-r--r--drivers/media/usb/em28xx/em28xx.h2
2 files changed, 10 insertions, 0 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c
index 26cf431b1a46..74575e0ed41b 100644
--- a/drivers/media/usb/em28xx/em28xx-audio.c
+++ b/drivers/media/usb/em28xx/em28xx-audio.c
@@ -293,7 +293,12 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
mutex_unlock(&dev->lock);
}
+ /* Dynamically adjust the period size */
snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+ snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+ dev->adev.period * 95 / 100,
+ dev->adev.period * 105 / 100);
+
dev->adev.capture_pcm_substream = substream;
return 0;
@@ -803,6 +808,9 @@ static int em28xx_audio_urb_init(struct em28xx *dev)
em28xx_info("Number of URBs: %d, with %d packets and %d size",
num_urb, npackets, urb_size);
+ /* Estimate the bytes per period */
+ dev->adev.period = urb_size * npackets;
+
/* Allocate space to store the number of URBs to be used */
dev->adev.transfer_buffer = kcalloc(num_urb,
diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h
index 5d5d1b6f0294..10b817245f7e 100644
--- a/drivers/media/usb/em28xx/em28xx.h
+++ b/drivers/media/usb/em28xx/em28xx.h
@@ -505,6 +505,8 @@ struct em28xx_audio {
unsigned int hwptr_done_capture;
struct snd_card *sndcard;
+ size_t period;
+
int users;
spinlock_t slock;
};