[PATCH] tty/8250_pnp: serial port detection regression since v3.7

From: Sean Young
Date: Fri Feb 22 2013 - 11:27:29 EST


The InsydeH2O BIOS (version dated 09/12/2011) has the following in
its pnp resouces for its serial ports:

$ cat /sys/bus/pnp/devices/00:0b/resources
state = active
io disabled
irq disabled

We do not check if the resources are disabled, and create a bogus
ttyS* device. Since commit 835d844d1a28e (8250_pnp: do pnp probe
before legacy probe) we get a bogus ttyS0, which prevents the legacy
probe from detecting it.

Reported-by: Vincent Deffontaines <vincent@xxxxxxxxxx>
Tested-by: Vincent Deffontaines <vincent@xxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/tty/serial/8250/8250_pnp.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_pnp.c b/drivers/tty/serial/8250/8250_pnp.c
index 35d9ab9..b3455a9 100644
--- a/drivers/tty/serial/8250/8250_pnp.c
+++ b/drivers/tty/serial/8250/8250_pnp.c
@@ -429,6 +429,7 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
{
struct uart_8250_port uart;
int ret, line, flags = dev_id->driver_data;
+ struct resource *res = NULL;

if (flags & UNKNOWN_DEV) {
ret = serial_pnp_guess_board(dev);
@@ -439,11 +440,12 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
memset(&uart, 0, sizeof(uart));
if (pnp_irq_valid(dev, 0))
uart.port.irq = pnp_irq(dev, 0);
- if ((flags & CIR_PORT) && pnp_port_valid(dev, 2)) {
- uart.port.iobase = pnp_port_start(dev, 2);
- uart.port.iotype = UPIO_PORT;
- } else if (pnp_port_valid(dev, 0)) {
- uart.port.iobase = pnp_port_start(dev, 0);
+ if ((flags & CIR_PORT) && pnp_port_valid(dev, 2))
+ res = pnp_get_resource(dev, IORESOURCE_IO, 2);
+ else if (pnp_port_valid(dev, 0))
+ res = pnp_get_resource(dev, IORESOURCE_IO, 0);
+ if (pnp_resource_enabled(res)) {
+ uart.port.iobase = res->start;
uart.port.iotype = UPIO_PORT;
} else if (pnp_mem_valid(dev, 0)) {
uart.port.mapbase = pnp_mem_start(dev, 0);
--
1.7.2.5

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