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 Post subject: Passing through keyboard LEDs in QEMU
PostPosted: Thu Mar 08, 2018 12:33 pm 
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Hello everyone, glad to see such an active OS Development forum! :o

Anyways, I want to test my keyboard LEDs where I actually want to output some debug info when in that mode. Only problem is that QEMU doesn't seem to create a direct tunnel from the emulated OS to the keyboard. I don't really want to keep moving the new compiled OS to a thumb drive and restart my computer just to see if a tiny change did the trick. Is there any way to fix/do this?

(If there is a possibility, it apparently is quite obscure, couldn't find anything on that subject... :| )


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 Post subject: Re: Passing through keyboard LEDs in QEMU
PostPosted: Thu Mar 08, 2018 2:02 pm 
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I like Qemu for a lot of things, probably the most is that it is quick. Hence the name. However, in my opinion, it lacks quite a few things.

I also use Bochs, and have even written a lot of the "external" parts of it, namely the USB as well as some of the floppy and hard drive stuff. The advantage to bochs is that it has a considerable amount of debugging capabilities as well as a single step capable debugger. The disadvantage, it is quite slow, in fact it is probably the slowest of all the emulators I know and use.

For you, the advantage would be that the LED state is displayed on the status bar of the Bochs window. i.e.:, when the Caps Lock is pressed within the quest, the Host shows it on the status bar of the Host Window. No need to reboot each time you make a small modification.

However, please note that Bochs is quite a bit slower than Qemu, though it is much faster than the process of writing to a USB drive, rebooting to test, then rebooting back to your development environment.

Try it and see what you think
Ben
-- http://www.fysnet.net/osdesign_book_series.htm

Bochs SVN:
https://sourceforge.net/p/bochs/code/HEAD/tree/
or a downloadable executable:
https://sourceforge.net/projects/bochs/


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 Post subject: Re: Passing through keyboard LEDs in QEMU
PostPosted: Thu Mar 08, 2018 10:27 pm 
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QEMU exposes the guest LED state when using vnc (or spice) protocol.

TigerVNC commit shows that it intends to synchronize the led state between the client and the server.


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 Post subject: Re: Passing through keyboard LEDs in QEMU
PostPosted: Fri Mar 09, 2018 1:54 pm 
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I figured there would be some way to do it, though I have not dug far into Qemu other than as an end-user product. I have not compiled, nor modified it in anyway. Bochs, on the other hand, well....

Since there was no response from the OP, I figured/was hoping that he/she had found Bochs and was too enthralled in it to respond. :-)

Ben


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