mISDN: Add feature via MISDN_CTRL_FILL_EMPTY to fill fifo if empty

This prevents underrun of fifo when filled and in case of an underrun it
prevents subsequent underruns due to jitter.
Improve dsp, so buffers are kept filled with a certain delay, so moderate
jitter will not cause underrun all the time -> the audio quality is highly
improved. tones are not interrupted by gaps anymore, except when CPU is
stalling or in high load.

Signed-off-by: Andreas Eversberg <andreas@eversberg.eu>
Signed-off-by: Karsten Keil <kkeil@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/isdn/hardware/mISDN/hfc_multi.h b/drivers/isdn/hardware/mISDN/hfc_multi.h
index 6d74951a1797..4aa6a8b41f50 100644
--- a/drivers/isdn/hardware/mISDN/hfc_multi.h
+++ b/drivers/isdn/hardware/mISDN/hfc_multi.h
@@ -9,6 +9,7 @@
 #define DEBUG_HFCMULTI_MODE     0x00100000
 #define DEBUG_HFCMULTI_MSG      0x00200000
 #define DEBUG_HFCMULTI_STATE    0x00400000
+#define DEBUG_HFCMULTI_FILL     0x00800000
 #define DEBUG_HFCMULTI_SYNC     0x01000000
 #define DEBUG_HFCMULTI_DTMF     0x02000000
 #define DEBUG_HFCMULTI_LOCK     0x80000000
@@ -166,6 +167,8 @@ struct hfc_multi {
 
         u_long          chip;   /* chip configuration */
         int             masterclk; /* port that provides master clock -1=off */
+        unsigned char   silence;/* silence byte */
+        unsigned char   silence_data[128];/* silence block */
         int             dtmf;   /* flag that dtmf is currently in process */
         int             Flen;   /* F-buffer size */
         int             Zlen;   /* Z-buffer size (must be int for calculation)*/