[Klug-general] Virtualbox woes

[Andrew Miller (Spode)]

This makes a lot of sense.

I know a friend of mine had a similar issue having multiple sound cards 
in his computer.

Mike Evans wrote:
> Dan and I just had a convo on IRC but I thought I'd document the 
> outcome for the benefit of everyone.  (Yes something that could go on 
> the website, but not tonight, I'm tired.)
>
> Basically if you have a usb sound device plugged in at boot the 
> chances are the usb sound driver will get loaded before your regular 
> sound card driver.  This has the effect of pushing your sound card 
> driver from number '0' to number '1'.  Of course your alsa 
> configuration has no way to know that's what happened and applies all 
> the wrong settings to everything.
>
> You can verify this by unplugging the USB device and rebooting and 
> sound is probably restored as the sound card will be in the '0' 
> position. Plug in the USB device after boot and it takes the number 
> '1' slot and you're probably still good.  Reboot with it plugged in 
> and they swap round again.  It would be possible to tweak your alsa 
> configuration, but then it would be wrong if ever you booted without 
> the usb device.
>
> The answer for me was to dictate the order of the device numbers in 
> the modprobe.conf file where I have the following lines:
>
> alias snd-card-0 snd-ens1371
> options snd-ens1371 index=0
> options snd_usb_audio index=1
>
> As a result of this my sound card with the ens1371 driver is 
> consistently in position 0, and the webcam with its built in 
> microphone is in position 1.
>
> For some reason the speaker applet thingy on my gnome taskbar is still 
> a little confused as it now always shows that the device is muted, but 
> I get sound just fine.  I'll try to sus that out one day.
>
> Incidentally there is a similar problem with the on-board modem driver 
> module.  Even if you don't use it, if your distro ships with it it 
> will probably load before the main sound card driver and then nothing 
> works.  (You get some message about a semaphore not being ready in 
> dmesg.) Ubuntu doesn't install the modem to sound card driver out of 
> the box - but if you click on the 'install restricted drivers' bit for 
> it then you will be in the same position as that's what happened to me 
> on my laptop.  I believe there is a way to get them to load in the 
> other order, but I found the web page once for it and can't track it 
> down again.  The answer for me on this one has been to blacklist the 
> modem bit as I don't need it right now.  The blacklisting is done 
> using a similar mechanism in the modprobe file(s) and if anyone needs 
> it I'll look it up on my laptop.
>
> I had unpredictable sound card behaviour for ages before I discovered 
> this stuff.  You can find it on various howtos and forums, but not all 
> in one place.
>
> The answer lies in doing an lsmod with the usb device plugged in at 
> boot and one with it not there.  Compare the two and the additional 
> modules are what's causing the problem.  You just have to figure out 
> what to do about it.
>
> MikeE
>
>
> Dan Attwood wrote:
>> after the discussion at the last meeting about virtualbox I decided 
>> to give usb support another go.
>>
>> I followed the various info on spodes site and on several other 
>> resources and soon add usb support running and was was happily mixed 
>> some banging tunes on with my usb mixer in propellerheads reason 
>> running in seamless mode on windows xp.
>>
>> and then I rebooted
>>
>> oh dear
>>
>> Now I get a message at boot time telling me that alsa failed to 
>> start. Then when I get into gnome sound in totem doesn't work - the 
>> volume slider is even greyed out. Sound in amarok is fine though. To 
>> add insult to injury the usb support stopped work as well.
>>
>> Anyone got any bright ideas?
>>
>>
>> ------------------------------------------------------------------------
>>
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>
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