ussr/bk: quickload and switchable b&w/color output

[shattered]

No description provided.

[MooglyGuy]

To make the code more informative, I would rename "extra button" to "color toggle button" or something similar, and rename update_monitor to update_monitor_type.

Also, why the rename from screen_update to screen_update_10? Although it's not an override, by convention the function tends not to be changed from screen_update unless there is a reason to do so, and in this case it's the only screen-update function in the driver.

[shattered]

extra_button rename makes sense.

bk0011 model has a bit more complex video hardware (two framebuffers, palettes, vblank irq). Some recent releases use mid-screen palette switching, so I'm planning to use a separate screen_update_11 and a scanline timer to implement that.

[MooglyGuy]

At that point, would it make more sense to subclass the driver and simply override the base screen_update entirely?

[shattered]

Maybe, but I'd like to get the WIP code out of the door first

[ajrhacker]

I don't understand why there needs to be a hacky extra input in the keyboard device here.

[shattered]

Purely for usability -- it's a bit clunky to toggle the configuration bit via UI.