On Mon, 24 Nov 2008, Jatin Kumar wrote:

On Wed, Nov 19, 2008 at 3:35 AM, Geert Uytterhoeven [off-list ref]wrote:

quoted

On Tue, 18 Nov 2008, Jatin Kumar wrote:

quoted

I am new to linux fb model and had some queries regarding resolution

change

quoted

mechanisms.

Consider a situation where the frambuffer kernel module (vfb/xenfb etc)
wants to change the resolution.

1. Is there a mechanism to this, considering the applications/windowing
system/console above the framebuffer hasnt initiated the size change?

2. Is there a way to do an upcall into the application/windowing
system/console modules to inform them about the size change

asynchronously?

quoted

In this particular case ; the display hardware(instead of the user) has
initiated the resolution change.Is it possible in the current fb

framework

quoted

to support it?

Yes there is! If the resolution is changed, and the number of columns and
lines of the console changes, the tty subsystem will send the SIGWINCH
signal
to the application, cfr. tty_do_resize() in drivers/char/tty_io.c.

Note that not all applications handle it. E.g. X doesn't, AFAIK.

Thanks much for the info.

Is the tty_io_resize( ) relatively new? .

tty_do_resize

I am looking at 2.6.18.8 src code (used for xen) and could not find the
function.

No, it's older than the frame buffer device framework. If you can't find it,
search for SIGWINCH.

Also are there any plans for exposing a similar callback api in the linux fb
model to make the applications stay updated about the underlying
resolution/hardware mode changes?

What exactly are you missing that SIGWINCH doesn't provide?

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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