Fix tdmtsak behaviour when tsak is restarted due to hardware changes

tdmlib/tdmtsak.cpp

@@ -157,8 +157,21 @@ int main (int argc, char *argv[])
 		}
 		close(mPipe_fd);
 		// Now wait for SAK press
-			mPipe_fd = open(FIFO_FILE, O_RDONLY);
 		while (mPipe_fd > -1) {
+			mPipe_fd = open(FIFO_FILE, O_RDONLY);
+
+			if (mPipe_fd <= -1) {
+				// This may be a transient glitch, such as when a KVM is being toggled or a new keyboard has been added
+				// Wait up to 5 seconds while trying to open the pipe again
+				int timeout = 5;
+				while ((mPipe_fd <= -1) && (timeout > 0)) {
+					sleep(1);
+					mPipe_fd = open(FIFO_FILE, O_RDONLY);
+					timeout--;
+				}
+			}
+
+			if (mPipe_fd > -1) {
 				numread = read(mPipe_fd, readbuf, 6);
 				readbuf[numread] = 0;
 				readbuf[127] = 0;
@@ -183,7 +196,9 @@ int main (int argc, char *argv[])
 					usleep(100);
 				}
 			}
+
 			close(mPipe_fd);
+		}
 		return 6;
 	}
 	else {