From f34244a871310fac4ab27f3fd75dc44626ed4eb9 Mon Sep 17 00:00:00 2001
From: "Michael F. Lamb" <mike@datagrok.org>
Date: Wed, 13 Mar 2019 14:00:09 -0700
Subject: [PATCH] Sleep until USB port becomes writable before running avrdude
 (#5393)

* sleep until usb port becomes writable before running avrdude

* only wait for a writable USB port when not on MSYS

using MINGW or MSYS: sleep for one second, as before.

otherwise: wait for the port to become writable.

* typo

* typo
---
 tmk_core/avr.mk | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tmk_core/avr.mk b/tmk_core/avr.mk
index d22c3bbcad..79fdf4de53 100644
--- a/tmk_core/avr.mk
+++ b/tmk_core/avr.mk
@@ -214,12 +214,15 @@ define EXEC_AVRDUDE
 			mv /tmp/2 /tmp/1; \
 		done; \
 		echo ""; \
-		echo "Detected controller on USB port at $$USB"; \
+		echo "Device $$USB has appeared; assuming it is the controller."; \
 		if $(GREP) -q -s 'MINGW\|MSYS' /proc/version; then \
 			USB=`echo "$$USB" | perl -pne 's/\/dev\/ttyS(\d+)/COM.($$1+1)/e'`; \
 			echo "Remapped MSYS2 USB port to $$USB"; \
+			sleep 1; \
+		else \
+			printf "Waiting for $$USB to become writable."; \
+			while [ ! -w "$$USB" ]; do sleep 0.5; printf "."; done; echo ""; \
 		fi; \
-		sleep 1; \
 		avrdude -p $(MCU) -c avr109 -P $$USB -U flash:w:$(BUILD_DIR)/$(TARGET).hex; \
 	fi
 endef