VirtualBox 4.1.4/Snow Leopard 10.6.8 on a ThinkPad X220 (help with sound!)

[bilditup1]

Hey all-

After a long hiatus from Mac hackery I finally decided to try osx86 again in the wake of El Jobso's death and because I finally have a computer that's easy to do virtualization on, an i7 ThinkPad X220. I've come to report my findings and ask for help.

 

 

VirtualBox EFI

Contrary to popular belief, the EFI implementation built-in to VirtualBox can boot the system properly, albeit very slowly. This is great because Shutdown/Restart doesn't cause a kernel panic, and About This Mac doesn't cause Finder to restart. (Note that on Sandy Bridge-based systems like mine, you'll have to get the 10.8.0 kernel to avoid a kernel panic; my solution was to use a bootloader disc image that included it and then to run the 10.6.8 update. Alternatively, one can simply acquire the 10.8.0 kernel and change com.apple.Boot.plist to point to it until you decide to upgrade).

 

Screen resolution

The cost of this though is looong startup times while the kernel and extensions are loaded, and no ability to change resolution via changing Boot.plist/adding a CustomVideoMode to your VirtualBox configuration. One might be able to use the alternative method of selecting between several hardcoded resolutions via 'GOP', but I didn't try this as the hard-coded resolutions aren't useful on a 12.5" 1366x768 native screen.

 

[url="http://www.insanelymac.com/forum/topic/279450-why-insanelymac-does-not-support-tonymacx86/"]#####[/url]/Chimera

The solution was to use tonymac's [url="http://www.insanelymac.com/forum/topic/279450-why-insanelymac-does-not-support-tonymacx86/"]#####[/url] installer to get the Chimera bootloader on there; afterwards Shutdown/Restart are no longer graceful and 'About This Mac' doesn't work, but changing resolution via com.apple.Boot.plist and adding "CustomVideoMode1" works fine.

All updates to date, including SecUpd 2011-006, install without issue. XCode 4.0.2, iTunes 10.5, Safari 5.1.1 - all up and running. (Needless to say, networking works fine, too.)

 

Sound

But sound doesn't. It seemed to be working during my initial install of 10.6 without any problems (was playing fine while putting in my initial info). After upgrading to 10.6.8 (immediately afterward) it stopped though. VirtualBox is configured to present an Intel HD Audio device.

• At first I tried to use several different flavors of VoodooHDA. While most of them recognized my device and produced sound, it was garbled and pitched down/running too slow/sampled at a very low rate (though sometimes it 'breaks through' in the middle of a song and samples properly, which is very jarring). This was true both when using my computer's built-in Conexant 20672 audio and with a HotAudio DAC Destroyer (though problems were a little more bearable on the latter, some of the time). Tweaks like setting 'Vectorize' to 'true' in the Info.plist of the kext changed nothing for me; so I gave up and eradicated it from my system.
  
• Reading a bit more I found that some people were claiming that the vanilla AppleHDA kext worked fine, without patching (uh which should have occurred to me considering that audio worked at first), so then I tried a few version of that by downloading Combo Updates and extracting AppleHDA.kext via Pacifist. All of the following I tested with 10.6.8.
  
• The one that ships with 10.6.8 (2.0.5) doesn't work at all (the kext doesn't load).
  
• The one that ships with 10.6.6 (1.9.9) suffers from VoodooHDA like problems - especially with the sampling rate, but also suffers from crackling. Using external DAC makes it a little more bearable, but not much.
  
• The one that ships with 10.6.6 (1.7.9) is interesting. With the built-in audio, the sampling rate is jumpy and crackling abounds, but with my external DAC it works almost without issue - some random crackling but otherwise, some very pure sound; no slowdown and no sampling rate shenanigans.
  
• The one that ships with 10.6.0 (1.7.4) doesn't work at all (kext doesn't load).
  
• I tried changing the Audio setting in VirtualBox to AC97and then using a custom driver purportedly made for VirtualBox AC97, but I got the same problems as 1.9.9 except worse.
  

So does anybody know, definitively, what driver I should be using?

And I just want to confirm - due to the lack of guest additions, video acceleration is impossible, right?

 

cheers,

-e

 

EDIT: Wow is that sig old

I also kept a working 10.6.8 image that doesn't use Chimera/is still on VirtualBox's EFI, in case it turns out some solution presents itself here that lets me use it at full resolution. Would 'editing DSDT' help? I'm not sure how to do this and if it's even relevant when virtualizing instead of doing a native install. Thanks in advance...