Re: [AD] fbcon backgrounding

[Grzegorz Adam Hankiewicz <gradha@xxxxxxxxxx>]

> > Running exswitch, if I select SWITCH_BACKAMNESIA then switch to
> > another VT, graphics that are drawn will be visible on screen.
>
> Now, the ideal thing would be that there existed a '/dev/null' graphic
> driver, and Allegro could set it up generically with SWITCH_BACKAMNESIA
> (which would eliminate any possible related problems with other
> drivers). Other than that, I think that the only possible thing would be
> to do something in fb_save() at src/linux/fbcon.c:456, like invalidating
> there all drawing calls (only with SWITCH_BACKAMNESIA) until we get a
> SWITCH_IN event.

The attached patch is a stupid approach to this: whenever a SWITCH_OUT
event comes, it creates a /dev/null like mapping and substitutes the
fbaddr. However, it just doesn't work, because fbaddr is not used at all,
but the BITMAP created with _make_bitmap and returned through fb_init.

I don't see any way this could be fixed at the driver level, because
it's Allegro one level up which controls the screen pointer. Suggestions?

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