Messages in this thread Patch in this message | | | From | Nicolas Ferre <> | Subject | [RFC PATCH] tty/serial: atmel: fix TX path in atmel_console_write() | Date | Wed, 15 Mar 2017 16:29:48 +0100 |
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A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") is that the console can be called with TX path disabled. Then the system would hang trying to push charecters out in atmel_console_putchar().
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") Cc: stable <stable@vger.kernel.org> # 4.4+ --- Hi Richard,
I found this to fix the problem with system hang in my linux-4.4-at91 branch (in the atmel_console_putchar() waiting loop actually). I'm open to more insignt. As we cannot figure out if this bit is set or not, I didn't preserve the current status...
Regards,
drivers/tty/serial/atmel_serial.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index dcebb28ffbc4..7372dbdb7a4c 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -2483,6 +2483,9 @@ static void atmel_console_write(struct console *co, const char *s, u_int count) pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN; atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS); + /* Make sure that tx path is actually able to send characters */ + atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN); + uart_console_write(port, s, count, atmel_console_putchar); /* -- 2.9.0
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