From adad44a3a99dae529cc979bd4deb68bba8e9c61c Mon Sep 17 00:00:00 2001
From: px4dev <px4@purgatory.org>
Date: Fri, 14 Sep 2012 00:22:07 -0700
Subject: [PATCH] Avoid a possible issue where an interrupt can intervene at a
 critical point, possibly leading to excess bytes being transferred on the
 bus.

---
 nuttx/arch/arm/src/stm32/stm32_i2c.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/nuttx/arch/arm/src/stm32/stm32_i2c.c b/nuttx/arch/arm/src/stm32/stm32_i2c.c
index cca7a24aaa..2d1a7142c5 100644
--- a/nuttx/arch/arm/src/stm32/stm32_i2c.c
+++ b/nuttx/arch/arm/src/stm32/stm32_i2c.c
@@ -1198,6 +1198,10 @@ static int stm32_i2c_isr(struct stm32_i2c_priv_s *priv)
         {
           stm32_i2c_traceevent(priv, I2CEVENT_RCVBYTE, priv->dcnt);
 
+#ifdef CONFIG_I2C_POLLED
+          //irqstate_t state = irqsave();
+#endif
+
           /* Receive a byte */
 
           *priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
@@ -1209,6 +1213,11 @@ static int stm32_i2c_isr(struct stm32_i2c_priv_s *priv)
               stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, 0);  
             }
           priv->dcnt--;
+
+#ifdef CONFIG_I2C_POLLED
+          //irqrestore(state);
+#endif
+
         }
     }