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Access to hardware from guest OS

Posted: 26. Jun 2010, 21:59
by martinrousev
Hello

I was wondering what access the guest has to the hardware. I'm asking this because I have a very strange problem. I'm running Virtual Box on a laptop Dell Latitude D830 with NVidia NVS 140M video card. It has XP 64 bit as host OS. I needed to test something on Ubuntu so I installed version 10.4 on a guest OS. Ubuntu doesn't include NVidia drivers as default so I needed to install packages, read some forums etc. I ended up editing some config files. As a result I ruined the driver completely and the X wouldn't load at all. The strange part is that I ruined more than this because the video card wouldn't work properly even before the host OS loads. When it checks the hardware or when I'm in BIOS it has strange lines going across the screen and it blinks often. The host OS now loads in 640x480 mode with 16 colors.

If anyone can assist how to fix it and possibly prevent it in the future I'll be very thankful.

Regards,
Martin

Re: Access to hardware from guest OS

Posted: 26. Jun 2010, 22:11
by stefan.becker
You can only access external USB devices. Internal devices are emulated, for example the guest always see a Realtek ac97 Sound Codec, else if your guest has another sound hardware. Same for graphics.

Sohortly answer: Not possible.

Re: Access to hardware from guest OS

Posted: 26. Jun 2010, 22:35
by Sasquatch
If the VM is brand new, reinstall it. It's faster than trying to revert the changes you made. After that, check the links in my signature for more help. The VirtualBox FAQ clearly states the point about the video card.

Re: Access to hardware from guest OS

Posted: 27. Jun 2010, 09:07
by martinrousev
Thank you Sasquatch,
You probably haven't read my whole post. I'm more concerned with the damage I've done to my video card rather than the guest OS. Deleting the guest is no problem for me. Fixing the problems with my video card is bigger concern. What I wanted to know is if this damage could have come from me messing with the settings of the guest OS.

Re: Access to hardware from guest OS

Posted: 27. Jun 2010, 13:28
by Sasquatch
As the FAQ states, there is no direct access. No harm is done to your video card. Do you see anything strange on the host since you messed with the guest? I doubt it. Hardware doesn't break that easily.

Re: Access to hardware from guest OS

Posted: 27. Jun 2010, 15:32
by martinrousev
To answer your question I will quote my first post.
martinrousev wrote:...The strange part is that I ruined more than this because the video card wouldn't work properly even before the host OS loads. When it checks the hardware or when I'm in BIOS it has strange lines going across the screen and it blinks often. The host OS now loads in 640x480 mode with 16 colors.
Of course I cannot rule out that the hardware failure has nothing to do with the host and is pure coincidence.

Re: Access to hardware from guest OS

Posted: 27. Jun 2010, 21:41
by Sasquatch
Could be a case of bad luck. Doing the wrong thing at the wrong time. Did you change any cables or settings on the Host? It is possible the card got a power surge from your PSU upon reboot or something to break it. A colleague of mine had his card busted at work without any warning. The system just wouldn't boot at all until the graphics card was removed or replaced.