RTT not updating when single stepping

[ddowling]

I have been experimenting with the RTT support in BMP as it looks perfect for fast logging output. However there seems to be an issue with how the polling for rtt IO is performed when stepping through code with gdb.

Currently poll_rtt() is only called in main.c:60 when the while loop has gdb_target_running true. It breaks out of this loop when gdb_target_running goes false before calling the poll_rtt() function. Then the application is blocked waiting for new packets in the gdb_getpacket() and there is no RTT polling performed.

blackmagic/src/main.c

Lines 44 to 64 in 309a17c

	static void bmp_poll_loop(void)
	{
	SET_IDLE_STATE(false);
	while (gdb_target_running && cur_target) {
	gdb_poll_target();
	// Check again, as `gdb_poll_target()` may
	// alter these variables.
	if (!gdb_target_running || !cur_target)
	break;
	char c = gdb_if_getchar_to(0);
	if (c == '\x03' || c == '\x04')
	target_halt_request(cur_target);
	platform_pace_poll();
	#ifdef ENABLE_RTT
	if (rtt_enabled)
	poll_rtt(cur_target);
	#endif
	}
	SET_IDLE_STATE(true);

I think this can be fixed by ensuring poll_rtt() is called on exit from this loop. I can work a up patch and pull request if this will help.