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    SubjectRe: [PATCH 5/5] VT binding: Add new doc file describing the feature
    On 6/10/06, Antonino A. Daplas <> wrote:
    > > I may be looking at the problem a little differently. I see the
    > > drivers like fb, vga, etc as registering with the console and saying
    > > they are capable of providing console services. I then see the console
    > > system as opening one of the registered devices. A driver is free to
    > > register/unregister whenever it wants to as long as it isn't open by
    > > the console system. Console can only open one driver at a time.
    > No, this isn't true. You can have multiple console drivers active,
    > that's why you have a first and last parameter in take_over_console().
    > Thus at boot time, the system driver will take consoles 0 - 63.
    > Later on when a driver loads, it can take over consoles 0 - 7, leaving
    > consoles 8 - 63 to the system driver.
    > To put it another way, console drivers can register for consoles 0 - 63,
    > but the user may choose to use it only for consoles 0 - 7.
    > This is another reason for the system driver, it makes the unbinding
    > behavior predictable. Without a system driver, guessing which driver
    > replaces the just unbound one may become just a tad bit confusing for
    > the typical user.

    I find the whole console/tty layer to be quite confusing to talk
    about. I am mixing up console as in where printk goes and console the
    video card login device. The part about making everything equal was
    directed towards the printk output device.

    I see now that you can have tty0-7 assigned to a different console
    driver than tty8-63.
    Why do I want to do this?
    Why do we need 64 predefined tty devices?

    Googling around the only example I could find was someone with a VGA
    card and a Hercules card. They setup 8 consoles on each card.

    > > Over time it would nice if these all merged to a single
    > > interchangeable interface. I would really like to be able to
    > > dynamically switch to serial/net while debugging a video driver. Is
    > > there some fundamental reason why these can't be merged?
    > It's already possible to redirect the system messages to two different
    > console classes, ie with the boot parameter:
    > console=tty0,ttyS0 /* direct output to VT and serial console */
    > And you can already choose the console you want by adjusting /etc/inittab.

    How can I change where printk are going at run-time? I didn't know you
    could do that.

    Jon Smirl
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      Last update: 2006-06-11 01:47    [W:0.023 / U:59.408 seconds]
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