The autoconfig prints messages while holding the port's spinlock and that causes a deadlock when using serial console.
Signed-off-by: Flavio Leitner <[email protected]> --- drivers/tty/serial/8250/8250.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c index 8123f78..17e0c3f 100644 --- a/drivers/tty/serial/8250/8250.c +++ b/drivers/tty/serial/8250/8250.c @@ -1037,6 +1037,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) unsigned char save_lcr, save_mcr; struct uart_port *port = &up->port; unsigned long flags; + unsigned int old_capabilities; if (!port->iobase && !port->mapbase && !port->membase) return; @@ -1087,6 +1088,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) /* * We failed; there's nothing here */ + spin_unlock_irqrestore(&port->lock, flags); DEBUG_AUTOCONF("IER test failed (%02x, %02x) ", scratch2, scratch3); goto out; @@ -1110,6 +1112,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) status1 = serial_in(up, UART_MSR) & 0xF0; serial_out(up, UART_MCR, save_mcr); if (status1 != 0x90) { + spin_unlock_irqrestore(&port->lock, flags); DEBUG_AUTOCONF("LOOP test failed (%02x) ", status1); goto out; @@ -1132,8 +1135,6 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO); scratch = serial_in(up, UART_IIR) >> 6; - DEBUG_AUTOCONF("iir=%d ", scratch); - switch (scratch) { case 0: autoconfig_8250(up); @@ -1167,19 +1168,13 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) serial_out(up, UART_LCR, save_lcr); - if (up->capabilities != uart_config[port->type].flags) { - printk(KERN_WARNING - "ttyS%d: detected caps %08x should be %08x\n", - serial_index(port), up->capabilities, - uart_config[port->type].flags); - } - port->fifosize = uart_config[up->port.type].fifo_size; + old_capabilities = up->capabilities; up->capabilities = uart_config[port->type].flags; up->tx_loadsz = uart_config[port->type].tx_loadsz; if (port->type == PORT_UNKNOWN) - goto out; + goto out_lock; /* * Reset the UART. @@ -1196,8 +1191,16 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) else serial_out(up, UART_IER, 0); - out: +out_lock: spin_unlock_irqrestore(&port->lock, flags); + if (up->capabilities != old_capabilities) { + printk(KERN_WARNING + "ttyS%d: detected caps %08x should be %08x\n", + serial_index(port), old_capabilities, + up->capabilities); + } +out: + DEBUG_AUTOCONF("iir=%d ", scratch); DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name); } -- 1.7.11.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
