Re: Introducing the LCD-Linux project

From: James Simmons
Date: Thu Jul 29 2010 - 14:39:35 EST



> > 3) Invert the VT layer. Currently the console/printk driver is on top of
> > the tty layer. It would be nice to be able to only use a very light
> > weight vt printk without the VT tty on top for embedded platforms.
>
> No. printk hits console drivers why may or may not be frame buffer
> interfaces. Has done for a very long time. Keith Packard has also been
> doing stuff with crash time oops displays etc over an X display.

Correct. What I mean is have the ability to just register the console
driver but not the tty driver.

> > 4) Seperate out the VT emulation layer. Related to 3.
>
> Separate from what ?

We can still have a basic tty layer without the control characters, think
do_con_trol in vt.c, junk compiled into the kernel. Make it a options for
userland to do the vt100 emulation.

> > 5) Multiple independent VT support. Which brings up the question what
> > should the mapping of VCs to a VT look like.
>
> I would suggest we borrow the X idea and each VC is
>
> int display; /* Display it is on (for console flipping) */
> struct something *vt; /* VT which it is displaying */
> int x,y,w,h; /* Window onto vt */

/dev/tty[0-16] -> VT display 0
/dev/tty[17-31] -> VT display 1

etc.

At least that is how I handled it several years ago.

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