Only search through newly detected devices and discard ones that disappeared

1 files changed, 3 insertions, 2 deletions

diff --git a/tmk_core/avr.mk b/tmk_core/avr.mk
index 24722736e..e11ba2e23 100644
--- a/tmk_core/avr.mk
+++ b/tmk_core/avr.mk
@@ -175,10 +175,11 @@ avrdude: $(BUILD_DIR)/$(TARGET).hex check-size
                 ls /dev/tty* > /tmp/1; \
                 echo -e "Detecting USB port, reset your controller now.\c"; \
                 while [ -z $$USB ]; do \
-                        sleep 1; \
                         echo -e ".\c"; \
+                        sleep 0.5; \
                         ls /dev/tty* > /tmp/2; \
-                        USB=`diff /tmp/1 /tmp/2 | grep -o '/dev/tty.*'`; \
+                        USB=`comm -13 /tmp/1 /tmp/2 | grep -o '/dev/tty.*'`; \
+                        mv /tmp/2 /tmp/1; \
                 done; \
                 echo ""; \
                 echo "Detected controller on USB port at $$USB"; \