[SeaBIOS] [PATCH] optionrom: disallow int19 redirect for pnp roms.

[Gerd Hoffmann]

  Hi,

> > Kevin, would you feel easier about the Int19h vector restoration if it
> > were controlled by a new, static, config knob?
> 
> If we could do it safely that would be fine.  My fear is that it
> introduces a regression.  A new config option would be okay, but it
> doesn't sound like that will help, as it seems that once one narrows
> down the problem to a bad behaving optionrom, one could just as easily
> block that optionrom instead..

Well, as already mentioned, physical hardware seems to solve that with
an config option to enable/disable hooking int19.  Look here for
example:

https://superuser.com/questions/1000339/interrupt-19-capture-bios-option

(Which effectively gives the user a tool to deal with the mess the broken
 development workflow created).

Thats why I picked the path to just not allow int19 hooks.  For pnp
roms, non-pnp roms are still allowed to do that.  And we have the option
to refine the logic if needed, check whenever the pnp rom has a bev or
bcv for example.

I'm also trying to avoid a config option.  Asking the user to deal with
the mess isn't a good way IMHO ...

cheers,
  Gerd