samd/machine_uart: Fix lock-up in loopback mode if read buffer is full.

robert-hh · dpgeorge · commit 4dfee50a0be8 · 2025-03-27T11:39:02.000+11:00
Signed-off-by: robert-hh &lt;robert@hammelrath.com&gt;
diff --git a/ports/samd/machine_uart.c b/ports/samd/machine_uart.c
@@ -156,7 +156,8 @@ void common_uart_irq_handler(int uart_id) {
                 }
             }
             #endif
-        } else if (uart->USART.INTFLAG.bit.DRE != 0) {
+        }
+        if (uart->USART.INTFLAG.bit.DRE != 0) {
             #if MICROPY_HW_UART_TXBUF
             // handle the outgoing data
             if (ringbuf_avail(&self->write_buffer) > 0) {

Original file line number	Diff line number	Diff line change
`@@ -156,7 +156,8 @@ void common_uart_irq_handler(int uart_id) {`
`156`	`156`	`}`
`157`	`157`	`}`
`158`	`158`	`#endif`
`159`		`- } else if (uart->USART.INTFLAG.bit.DRE != 0) {`
	`159`	`+ }`
	`160`	`+ if (uart->USART.INTFLAG.bit.DRE != 0) {`
`160`	`161`	`#if MICROPY_HW_UART_TXBUF`
`161`	`162`	`// handle the outgoing data`
`162`	`163`	`if (ringbuf_avail(&self->write_buffer) > 0) {`