This is a note to let you know that I've just added the patch titled Revert "serial: imx: initialized DMA w/o HW flow enabled" to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-serial-imx-initialized-dma-w-o-hw-flow-enabled.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 907eda32a36fcdb979bdb91ea097abb3dd2c23c9 Mon Sep 17 00:00:00 2001 From: David Jander <david@xxxxxxxxxxx> Date: Fri, 26 Jun 2015 08:11:30 +0200 Subject: Revert "serial: imx: initialized DMA w/o HW flow enabled" From: David Jander <david@xxxxxxxxxxx> commit 907eda32a36fcdb979bdb91ea097abb3dd2c23c9 upstream. This reverts commit 068500e08dc87ea9a453cc4a500cf3ab28d0f936. According to some tests, SDMA support is broken at least for i.MX6 without HW flow control. Different forms of data-corruption appear either with the ROM firmware for the SDMA controller as well as when loading Freescale provided SDMA firmware versions 1.1 or 3.1. Signed-off-by: David Jander <david@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/imx.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1132,11 +1132,6 @@ static int imx_startup(struct uart_port while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0)) udelay(1); - /* Can we enable the DMA support? */ - if (is_imx6q_uart(sport) && !uart_console(port) && - !sport->dma_is_inited) - imx_uart_dma_init(sport); - spin_lock_irqsave(&sport->port.lock, flags); /* @@ -1145,9 +1140,6 @@ static int imx_startup(struct uart_port writel(USR1_RTSD, sport->port.membase + USR1); writel(USR2_ORE, sport->port.membase + USR2); - if (sport->dma_is_inited && !sport->dma_is_enabled) - imx_enable_dma(sport); - temp = readl(sport->port.membase + UCR1); temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN; @@ -1318,6 +1310,11 @@ imx_set_termios(struct uart_port *port, } else { ucr2 |= UCR2_CTSC; } + + /* Can we enable the DMA support? */ + if (is_imx6q_uart(sport) && !uart_console(port) + && !sport->dma_is_inited) + imx_uart_dma_init(sport); } else { termios->c_cflag &= ~CRTSCTS; } @@ -1434,6 +1431,8 @@ imx_set_termios(struct uart_port *port, if (UART_ENABLE_MS(&sport->port, termios->c_cflag)) imx_enable_ms(&sport->port); + if (sport->dma_is_inited && !sport->dma_is_enabled) + imx_enable_dma(sport); spin_unlock_irqrestore(&sport->port.lock, flags); } Patches currently in stable-queue which might be from david@xxxxxxxxxxx are queue-4.1/revert-serial-imx-initialized-dma-w-o-hw-flow-enabled.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html