From 040bad042544a8921678cfcc274c29e348cf767d Mon Sep 17 00:00:00 2001
From: Marian Buschsieweke <marian.buschsieweke@ovgu.de>
Date: Mon, 27 Jul 2020 09:42:07 +0200
Subject: [PATCH] cpu/atmega_common: increase stack size with xtimer

If a timer triggers while the idle thread is running, previously a stack
overflow was triggered. This commit increases the idle threads stack size if
xtimer is used.
---
 cpu/atmega_common/include/cpu_conf.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cpu/atmega_common/include/cpu_conf.h b/cpu/atmega_common/include/cpu_conf.h
index bd00d7e278..e97dd2fb0d 100644
--- a/cpu/atmega_common/include/cpu_conf.h
+++ b/cpu/atmega_common/include/cpu_conf.h
@@ -49,8 +49,16 @@ extern "C" {
  * to avoid not printing of debug in interrupts
  */
 #ifndef THREAD_STACKSIZE_IDLE
+#ifdef MODULE_XTIMER
+/* xtimer's 64 bit arithmetic doesn't perform well on 8 bit archs. In order to
+ * prevent a stack overflow when an timer triggers while the idle thread is
+ * running, we have to increase the stack size then
+ */
+#define THREAD_STACKSIZE_IDLE      (192)
+#else
 #define THREAD_STACKSIZE_IDLE      (128)
 #endif
+#endif
 /** @} */
 
 /**