diff options
| author |   Flavio Leitner <fbl@redhat.com> | 2012-09-18 16:21:32 -0300 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-21 09:53:15 -0700 |
| commit | bd21f551c365e50a241b4cee4bc8be72914ff236 (patch) | |
| tree | c67fce569d97f38504fd145bf1f173345aeedbec /drivers/tty/serial/8250/8250.c | |
| parent | pty: Fix locking bug on error path (diff) | |
| download | linux-dev-bd21f551c365e50a241b4cee4bc8be72914ff236.tar.xz linux-dev-bd21f551c365e50a241b4cee4bc8be72914ff236.zip | |
8250: fix autoconfig to work with serial console
The autoconfig prints messages while holding the
port's spinlock and that causes a deadlock when
using serial console.
Signed-off-by: Flavio Leitner <fbl@redhat.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/8250/8250.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250.c | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c index d4e0b07cb130..932a216aa5bc 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); } |