Re: [PATCH 1/2] Define FIXED_PORT flag for serial_core

On Thu, Mar 01, 2007 at 10:44:24AM +1100, David Gibson wrote:

On Wed, Feb 28, 2007 at 10:26:30PM +0000, Russell King wrote:

quoted

On Tue, Feb 20, 2007 at 02:19:51PM +1100, David Gibson wrote:

quoted

Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port
structure.  If this flag is set when the serial port is configured,
any attempts to alter the port's type, io address, irq or base clock
with setserial are ignored.

I've been wondering about this, and it is questionable whether we
should allow any serial port which isn't owned by the legacy platform
device (the one called "serial8250", iow by the 8250 driver itself)
to have the base addresses and interrupts changed.

IOW, we apply this "fixed port" to any port registered by probe
modules external to the 8250 driver itself, such as PCI, PNP, etc.

Sounds reasonable to me.  But maybe in that case we should invert the
sense of the flag.  UPF_MOVABLE_PORT or UPF_USER_CONFIGURABLE or
something.

I was thinking about not even having a flag, but instead checking for
port->dev == &serial8250_isa_devs->dev.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of: