Re: 2.6.0-test11 -- Failed to open /dev/ttyS0: No such device

From: Russell King
Date: Sun Nov 30 2003 - 11:01:50 EST


On Mon, Dec 01, 2003 at 01:54:51AM +1000, Steve Youngs wrote:
> |--==> "JK" == Jacek Kawa <jfk@xxxxxxxxxxxxxxxxxxxxx> writes:
>
> JK> bert hubert wrote:
> >>> Does anyone have modem working in 2.6.0-test11?
> >>> I have external modem connected to /dev/ttyS0 (COM1). Kernel
> >>> 2.6.0-test11 give me
>
> JK> It reminds me, that I had to add serial to the list of modules
> JK> loading at start to get back access to /dev/ttyS*
> JK> (while upgrading from -test9 to -test10).
>
> Jacek,
>
> I _think_ this patch will bring back auto-loading of the serial module
> for you. Please let me know how it goes. (Bert, this won't fix your
> problem if you have the serial driver compiled directly into the
> kernel, but it might if you have it as a module.)
>
> --- linux-2.6.0-test11/drivers/serial/serial_core.c 2003-11-27 12:12:22.000000000 +1000
> +++ linux-2.6.0-test11-sy/drivers/serial/serial_core.c 2003-12-01 01:38:40.000000000 +1000
> @@ -2420,3 +2420,4 @@
>
> MODULE_DESCRIPTION("Serial driver core");
> MODULE_LICENSE("GPL");
> +MODULE_ALIAS_CHARDEV(drv->major, drv->minor);
>

This is wrong. serial_core should /never/ depend on a major/minor number
because it doesn't know what (group of) major/minor(s) it is going to be.

The only modules which know are the hardware drivers themselves, like
8250.c.

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