[PATCH] drm/bochs: Add screen blanking support

[Gerd Hoffmann]

> > However, a tricky part is that the QEMU vga code does treat VGA_ATT_IW
> > register always as "flip-flop"; the first write is for index and the
> > second write is for the data like palette.  Meanwhile, in the current
> > bochs DRM driver, the flip-flop wasn't considered, and it calls only
> > the register update once with the value 0x20.
> > 
> 
> Unless bochs does things very different, the index should first be reset by
> reading 0x3da. Then write the index, then the data.
> 
> https://web.stanford.edu/class/cs140/projects/pintos/specs/freevga/vga/vgareg.htm#attribute

bochs should follow standard vga logic here.
Also a bochs_set_blank(true/false) helper function probably makes sense.

take care,
  Gerd