Messages in this thread Patch in this message | | | Date | Sat, 23 Apr 2016 10:14:32 -0700 | From | Frank Rowand <> | Subject | [PATCH 1/2] tty: serial: msm_serial regression fix data corruption |
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From: Frank Rowand <frank.rowand@am.sony.com>
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 <frank.rowand@am.sony.com> 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
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