CMI8738 PCI-e Restarting PC \ VOGONS

CMI8738 PCI-e Restarting PC

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First post, by DieSkaarj

Posted on 2025-12-04, 11:12

DieSkaarj Offline

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Joined: 2024-12-29, 02:55

Hello Vogons,

Has anyone here had a similar experience where when playing sound a CMI8738 PCI-e card (as seen in PhilsComputerLab) just straight out restarts the PC?

For background I am trying to get this card working inside a Win98SE VM. However the instability is present wherever the card is in use, on Windows 11, Linux (Void,) and through QEMU. The peculiar thing is that there is more stability with it running inside the VM using the VxD drivers available from Vogons. The sounds play fine in the OS until a game is started and then the entire unit resets.

I have tried to reconfigure the BIOS by setting the PCI bus related options to gen_1,2. I have disabled the OnBoard HD Audio. It might be worth noting that I'm using an AM4+ board, the MSI B350 Gaming Plus with a 3200G CPU. And, it's not just that board that has the same behaviour. It's other AM4+ boards with different CPU's.

It's not the first CMI8738 card I've tried either as I thought the first one was faulty, with it being a cheap chinese shite-y clone, but same issue persists. Again, on another CSC (Cheap Shitey Clone.)

I suspected that it was perhaps a memory issue (ReBar was disabled in BIOS also,) and have got yer another CSC, one that is advertised as being 32/64 bit and compatible with Win10. But, there's no ground for thinking this other than marketing.

Can anyone advise or have another PCI-e soundcard suggestion that can work on 9x?

Best regards,
David

Reply 1 of 6, by LSS10999

Posted on 2025-12-06, 04:25

LSS10999 Offline

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Which PCI-PCIe bridge it uses? I think some PCI-e adapted CMI8738 cards use ASM1083 as bridge.

A little searching online seems to suggest this bridge is kind of VM-unfriendly...

Reply 2 of 6, by myne

Posted on 2025-12-06, 04:31

myne Offline

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Post bsod/logs.

No os crashes without at least attempting to report why.

I am presuming you men the host is rebooting.

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Reply 3 of 6, by DieSkaarj

Posted on 2025-12-06, 10:27

DieSkaarj Offline

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Joined: 2024-12-29, 02:55

It is using the ASM108 but I have an Xonar that uses the same bridge with no issues. Thanks for sharing that.

# dmesg | grep -iE "error|fail|warn"

1[    0.000000] Warning: PCIe ACS overrides enabled; This may allow non-IOMMU protected peer-to-peer DMA
2[    0.345304] pci 0000:20:04.0: bridge window [mem size 0x10000000 64bit pref]: failed to assign
3[    0.345307] pci 0000:20:04.0: bridge window [mem size 0x10000000 64bit pref]: failed to assign
4[    0.345371] pci 0000:25:00.0: BAR 0 [mem 0x7fc0000000-0x7fcfffffff 64bit pref]: failed to assign
5[    0.345374] pci 0000:25:00.0: BAR 0 [mem 0x7fc0000000-0x7fcfffffff 64bit pref]: failed to assign
6[b][    0.365280] x86/amd: Previous system reset reason [0x08000800]: an uncorrected error caused a data fabric sync flood event[/b]
7[    4.709451] amdgpu 0000:30:00.0: amdgpu: psp gfx command LOAD_TA(0x1) failed and response status is (0x7)
8[    5.607482] vhba: module verification failed: signature and/or required key missing - tainting kernel
9[    5.815215] faux_driver regulatory: Direct firmware load for regulatory.db failed with error -2
10[    5.815221] cfg80211: failed to load regulatory.db

The host restarts regardless of OS but the above is the post restart dmesg output.

I'll tinker with C-States and Memory speeds, as indicated from the error code 0x08000800.

Reply 4 of 6, by myne

Posted on 2025-12-06, 11:17

myne Offline

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Yeah, wow.
That error seems to have only existed online this year and is AMD specific.
Definitely an interesting one.

If your hardware isn't fairly cutting edge try... downgrading kernel?
Or if the kernel is old, upgrade?

Reply 5 of 6, by DieSkaarj

Posted on 2025-12-06, 21:19

DieSkaarj Offline

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Joined: 2024-12-29, 02:55

I downgraded to 5.4, compiled from source, with no luck.

Hmm, I think I'm out of luck here, well unless it becomes a big enough issue that AMI fix it.

I also compiled the dev branch of 86Box as it has experimental VFIO support. However there is an issue with my ATI x800 card, but it does emulate that CMI8738 chip!

Thank you both for your help here.

Reply 6 of 6, by myne

Posted on 2025-12-06, 23:51

myne Offline

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Bummer.
Well, at least you mostly know.

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