sercomm_cons: Utilize msgb's better, don't always end at \n

In the sercomm_cons layer, ee used to enqueue a msgb for sending
every time there is an end-of-line.  However, if we send a number
of very short lines, we easily run out of msgbs.

Now we check how much msgb backlog there is in the transmit queue,
and decide to skip the end-of-line flushing if needed.

This still doesn't solve all our problems, but its still a useful
mechanism.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/target/firmware/comm/sercomm_cons.c b/src/target/firmware/comm/sercomm_cons.c
index fa08b50e..5b481bcb 100644
--- a/src/target/firmware/comm/sercomm_cons.c
+++ b/src/target/firmware/comm/sercomm_cons.c
@@ -91,8 +91,11 @@ int sercomm_puts(const char *s)
 		{
 			unsigned int i;
 			for (i = 0; i < write_num; i++) {
-				/* flush buffer at end of line */
-				if (*s == '\n')
+				/* flush buffer at end of line, but skip
+				 * flushing if we have a backlog in order to
+				 * increase efficiency of msgb filling */
+				if (*s == '\n' &&
+				    sercomm_tx_queue_depth(SC_DLCI_CONSOLE) < 4)
 					flush = 1;
 				*data++ = *s++;
 			}