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    SubjectRe: How do I choose an arbitrary minor number for my tty device?
    Alan Cox wrote:
    > Your console driver provides a device method (see kernel/printk.c).
    > When /dev/console is opened the kernel iterates the console list looking
    > for one with ->device and then calls that method. On success it expects
    > the passed int * to contain the minor number to use.

    Are you talking about this:

    static struct tty_driver *ehv_bc_console_device(struct console *co, int *index)
    *index = co->index;

    return ehv_bc_driver;

    I never really understood this function, but almost everyone does the same
    thing, and it seems to work for me. Looking at console_device(), it appears
    that all of the xxx_console_device functions are called in order until one of
    them returns non-NULL.

    How is this related to add_preferred_console()? When I call this function, I
    also specify the same index and the name from the struct console device:

    static struct console ehv_bc_console = {
    .name = "ttyEHV",
    .write = ehv_bc_console_write,
    .device = ehv_bc_console_device,

    add_preferred_console(, ehv_bc_console.index, NULL);

    > I suspect in your case you probably want to attach the primary byte
    > channel to minor 0 in the driver (and reserve it for that), or some
    > similar rule.

    Yes, that's a good idea. It does simplify things a lot.

    Timur Tabi
    Linux kernel developer at Freescale

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      Last update: 2010-11-23 18:19    [W:0.034 / U:0.024 seconds]
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