flat assembler
Message board for the users of flat assembler.

Index > DOS > Fn + F6 key program?

Author
Thread Post new topic Reply to topic
fonolite



Joined: 14 Dec 2005
Posts: 32
fonolite 17 Jul 2014, 07:47
In my Dell laptop, Fn + F6 is Video Output button. (i.e LCD Off and D-sub Monitor On)

How can I write some programs to do this function?

When I hook INT 9 in real mode, this fn+f6 doesn't do INT 9 (IRQ1).
Post 17 Jul 2014, 07:47
View user's profile Send private message Reply with quote
baldr



Joined: 19 Mar 2008
Posts: 1651
baldr 17 Jul 2014, 14:23
fonolite,

Fn+key combinations are (most probably) handled by BIOS code running in SMM. While it may be possible to examine SMRAM contents' disassembly and find appropriate instructions' sequence, I suppose you can find datasheet for your videocontroller that contains the information that code is based upon.
Post 17 Jul 2014, 14:23
View user's profile Send private message Reply with quote
axlucas



Joined: 02 May 2014
Posts: 68
Location: Argentina
axlucas 18 Jul 2014, 06:52
It may well also be completely impossible. I've seen some combinations of Fn + key returning scan codes that are impossible to differentiate from single keys on a desktop keyboard. I reckon hardware functions could be present, that is, in this case, the key combination could directly trigger a hardware switch instead of going through the BIOS.
If normally, when you press a Fn key combination, you see a pop up on the screen with some graphics, it could be software based, but "silent" keys may be just hard wired.
Of course, I'm just guessing.
Post 18 Jul 2014, 06:52
View user's profile Send private message Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 19873
Location: In your JS exploiting you and your system
revolution 18 Jul 2014, 12:05
"Hard wired" keys is very unlikely. Too much effort to make such a thing. The chips used in keyboards are extremely cheap and generic and there is no need for a manufacturer to use something custom. So based upon that all keys are handled by software. Be that the OS kernel or SMM it will all be software processed.
Post 18 Jul 2014, 12:05
View user's profile Send private message Visit poster's website Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  


< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2023, Tomasz Grysztar. Also on GitHub, YouTube.

Website powered by rwasa.