From 4e4e66029af090c98cb10fafd13e8dd5039037a9 Mon Sep 17 00:00:00 2001 From: Volker Ernst Date: Wed, 13 Oct 2010 11:03:57 +0200 Subject: [PATCH] serial/imx: check that the buffer is non-empty before sending it out MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The .start_tx callback (imx_start_tx here) isn't only called when the buffer is non-empty. E.g. after resume or when handshaking is enabled and the other side starts to signal being ready. So check for an empty puffer already before sending the first character. This prevents sending out stale (or uninitialised) data. Signed-off-by: Volker Ernst Signed-off-by: Daniel Mack Cc: Andy Green [ukl: reword commit log, put check in while condition] Signed-off-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman --- drivers/serial/imx.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c index 66ecc7ab6da..dfcf4b1878a 100644 --- a/drivers/serial/imx.c +++ b/drivers/serial/imx.c @@ -327,14 +327,13 @@ static inline void imx_transmit_buffer(struct imx_port *sport) { struct circ_buf *xmit = &sport->port.state->xmit; - while (!(readl(sport->port.membase + UTS) & UTS_TXFULL)) { + while (!uart_circ_empty(xmit) && + !(readl(sport->port.membase + UTS) & UTS_TXFULL)) { /* send xmit->buf[xmit->tail] * out the port here */ writel(xmit->buf[xmit->tail], sport->port.membase + URTX0); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); sport->port.icount.tx++; - if (uart_circ_empty(xmit)) - break; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)