tty/8250_pnp: serial port detection regression since v3.7
authorSean Young <sean@mess.org>
Fri, 22 Feb 2013 16:27:19 +0000 (16:27 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 12 Mar 2013 15:53:23 +0000 (08:53 -0700)
commit77e372a3d82e5e4878ce1962207edd766773cc76
tree2d06807457960bd2da3f0dbc9ea18f16dbc04ace
parent064256feab4f94d2dc894b181e2f82769966f6c7
tty/8250_pnp: serial port detection regression since v3.7

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.

Note, the BIOS can also be upgraded, fixing this problem, but for people
who can't do that, this fix is needed.

Reported-by: Vincent Deffontaines <vincent@gryzor.com>
Tested-by: Vincent Deffontaines <vincent@gryzor.com>
Signed-off-by: Sean Young <sean@mess.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/8250/8250_pnp.c