[ISDN]: i4l: Fix DLE handling for i4l-audio
The DLE handling in i4l-audio seems to be broken.
It produces spurious DLEs so asterisk 1.2.24 with chan_modem_i4l
gets irritated, the error message is:
"chan_modem_i4l.c:450 i4l_read: Value of escape is ^ (17)".
-> There shouldn't be a DLE-^.
If a spurious DLE-ETX occurs, the audio connection even dies.
I use a "AVM Fritz!PCI" isdn card.
I found two issues that only appear if ISDN_AUDIO_SKB_DLECOUNT(skb) > 0:
- The loop in isdn_tty.c:isdn_tty_try_read() doesn't escape a DLE if it's
the last character.
- The loop in isdn_common.c:isdn_readbchan_tty() doesn't copy its characters,
it only remembers the last one ("last = *p;").
Compare it with the loop in isdn_common.c:isdn_readbchan(), that *does*
copy them ("*cp++ = *p;") correctly.
The special handling of the "last" character made it more difficult.
I compared it to linux-2.4.19: There was no "last"-handling and both loops
did escape and copy all characters correctly.
Signed-off-by: Matthias Goebl <matthias.goebl@goebl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c
index d695295..9cef6fc 100644
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -914,6 +914,9 @@
dflag = 0;
count_pull = count_put = 0;
while ((count_pull < skb->len) && (len > 0)) {
+ /* push every character but the last to the tty buffer directly */
+ if ( count_put )
+ tty_insert_flip_char(tty, last, TTY_NORMAL);
len--;
if (dev->drv[di]->DLEflag & DLEmask) {
last = DLE;