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path: root/drivers/media/usb/em28xx/em28xx-audio.c
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Diffstat (limited to 'drivers/media/usb/em28xx/em28xx-audio.c')
-rw-r--r--drivers/media/usb/em28xx/em28xx-audio.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c
index 6c7d34600294..f6fcee3d4fb9 100644
--- a/drivers/media/usb/em28xx/em28xx-audio.c
+++ b/drivers/media/usb/em28xx/em28xx-audio.c
@@ -52,6 +52,7 @@ MODULE_PARM_DESC(debug, "activates debug info");
#define EM28XX_MAX_AUDIO_BUFS 5
#define EM28XX_MIN_AUDIO_PACKETS 64
+
#define dprintk(fmt, arg...) do { \
if (debug) \
printk(KERN_INFO "em28xx-audio %s: " fmt, \
@@ -217,15 +218,26 @@ static struct snd_pcm_hardware snd_em28xx_hw_capture = {
.formats = SNDRV_PCM_FMTBIT_S16_LE,
- .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_KNOT,
+ .rates = SNDRV_PCM_RATE_48000,
.rate_min = 48000,
.rate_max = 48000,
.channels_min = 2,
.channels_max = 2,
.buffer_bytes_max = 62720 * 8, /* just about the value in usbaudio.c */
- .period_bytes_min = 64, /* 12544/2, */
- .period_bytes_max = 12544,
+
+
+ /*
+ * The period is 12.288 bytes. Allow a 10% of variation along its
+ * value, in order to avoid overruns/underruns due to some clock
+ * drift.
+ *
+ * FIXME: This period assumes 64 packets, and a 48000 PCM rate.
+ * Calculate it dynamically.
+ */
+ .period_bytes_min = 11059,
+ .period_bytes_max = 13516,
+
.periods_min = 2,
.periods_max = 98, /* 12544, */
};