[SOLVED] Sound Blaster Audigy RX and asfxload sound cutoff

[Pyro MX]

Hello everybody,

I stumbled across a peculiar problem with my sound card. I recently upgraded from a Sound Blaster Audigy 2 to a Sound Blaster Audigy RX since my Audigy 2 wasn't PCI express and my new motherboard doesn't have any PCI slots. I was used to play midi using the Audigy 2's hardware sequencer and asfxload to load the sound bank.

I tried to do the same setup with my new Audigy RX - since it used the same snd-emu10k1 and snd-emu10k1-synth modules, I thought that maybe, just maybe, things would still work. So here's what happens.

I can see the Emu10k1 midi ports all right when I do a "aplaymidi -l", however, if I try to load a sound bank (I tried the 2mb, 4mb and 8mb sound banks provided in the install CD) using either "rc-service sfxload start" or manually invoking "asfxload /usr/local/src/sounds/sf2/ct2mgm.sf2", all sound is cut off. Using aplaymidi on any port doesn't yield anything and sound is off everywhere (cannot even play OGGs). Unloading the sound bank and restarting ALSA won't help - only rebooting the machine will make sound work again. Mixer levels are untouched during the whole operation.

I know this is very specific and likely quite hard to reproduce elsewhere - if anything, I'll fall back to using fluidsynth, but I wanted to know if this rings a bell to anyone? Maybe you experienced a similar problem?

Thanks in advance!
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Pyro MX

[Pyro MX]

Well, my brother cracked the problem! We ran some tests tonight and we managed to reproduce the issue even though we were not using the same distro.

When invoking asfxload, an IO_PAGE_FAULT error would be visible from the kernel logs. After some digging, it turns out that IOMMU was causing the problem.

In my case, putting "iommu=soft" as a kernel boot param fixed the issue. Turning off IOMMU altogether from the UEFI could also fix it. Here's an interesting thread about it, with a Xonar card:

https://bbs.archlinux.org/viewtopic.php?id=168555

Hopefully this will be useful for anyone trying to make asfxload work on their box!
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Pyro MX