From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Rowand Subject: [PATCH 1/2] tty: serial: msm_serial regression fix data corruption Date: Sat, 23 Apr 2016 10:14:32 -0700 Message-ID: <571BAD78.4020609@gmail.com> References: <571BAC8B.80001@gmail.com> Reply-To: frowand.list@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <571BAC8B.80001@gmail.com> Sender: linux-arm-msm-owner@vger.kernel.org To: Andy Gross , David Brown , Greg Kroah-Hartman , Jiri Slaby , "linux-arm-msm@vger.kernel.org" , linux-soc@vger.kernel.org, linux-serial@vger.kernel.org, Linux Kernel list , ivan.ivanov@linaro.org List-Id: linux-serial@vger.kernel.org From: Frank Rowand Commit 3a878c430fd6 ("tty: serial: msm: Add TX DMA support") regression. The calculation of tx_count was moved from the old msm_handle_tx(), now renamed msm_handle_tx_pio(), to the new msm_handle_tx(). The move left out one size test. The regression seen on the qcom-apq8074-dragonboard is dropped characters and corrupted characters (values greater than 0x7f) when DMA is not enabled. Signed-off-by: Frank Rowand Cc: stable@vger.kernel.org --- drivers/tty/serial/msm_serial.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) Index: b/drivers/tty/serial/msm_serial.c =================================================================== --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -727,6 +727,8 @@ static void msm_handle_tx(struct uart_po } pio_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE); + pio_count = min3(pio_count, (unsigned int)UART_XMIT_SIZE - xmit->tail, + port->fifosize); dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); dma_min = 1; /* Always DMA */ @@ -738,9 +740,6 @@ static void msm_handle_tx(struct uart_po dma_count = UARTDM_TX_MAX; } - if (pio_count > port->fifosize) - pio_count = port->fifosize; - if (!dma->chan || dma_count < dma_min) msm_handle_tx_pio(port, pio_count); else