From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel@caiaq.de (Daniel Mack) Date: Wed, 6 Oct 2010 18:57:16 +0200 Subject: [PATCH] ARM: imx serial driver: fix resume Message-ID: <1286384236-4241-1-git-send-email-daniel@caiaq.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Volker Ernst I just came across a bug in the IMX31 serial driver which is still present in the newest kernels and which prevents successful resume-operation for the IMX31 serial ports. What happens is that in "drivers/serial/imx.c" on resume function "serial_imx_resume" gets called. This function in turn calls "uart_resume_port" (in the generic serial driver "serial_core.c"), which in turn calls "imx_start_tx" in "imx.c" (in case the SIO-port was really suspended) which in turn calls "imx_transmit_buffer". However calling "imx_transmit_buffer" with an empty TX-fifo (as is usually the case) will result in the serial port starting to transmit (actually the old [already sent] tx-buffer), as there is no check if the tx-buffer is empty before starting to feed tx-fifo-data to the serial port hardware. Signed-off-by: Volker Ernst Cc: Daniel Mack Cc: Andy Green --- Volker did all the work on this, he just doesn't want to push his great contributions upstream, so I do it for him :) drivers/serial/imx.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c index 66ecc7a..0170119 100644 --- a/drivers/serial/imx.c +++ b/drivers/serial/imx.c @@ -328,13 +328,13 @@ 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)) { + if (uart_circ_empty(xmit)) + break; /* 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) -- 1.7.0.4