drivers: serial: stm32: fix race condition when both APIs enabled (db15de52) · Commits · Wenxi XU / zephyr

Fix a bug where if CONFIG_UART_ASYNC_API was enabled in the config, the interrupt flags would get cleared after the interrupt driven API callback finished executing, causing data loss if data happened to arrive after the callback but before the flags were cleared. Signed-off-by:

Kamil Krzyżanowski <kamnxt@kamnxt.com>

drivers/serial/uart_stm32.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -1359,6 +1359,16 @@ static void uart_stm32_isr(const struct device *dev)
		#endif

		#ifdef CONFIG_UART_ASYNC_API
		#ifdef CONFIG_UART_INTERRUPT_DRIVEN
		/* If both ASYNC and INTERRUPT modes are supported in this build,
		* check whether this instance is currently being used via the
		* interrupt-driven API. If it is, do not process interrupt flags
		* as the user callback invoked earlier is responsible for that.
		*/
		if (data->user_cb) {
		return;
		}
		#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
		if (LL_USART_IsEnabledIT_IDLE(usart) &&
		LL_USART_IsActiveFlag_IDLE(usart)) {

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