Messages in this thread | | | Date | Mon, 22 Aug 2022 16:12:59 +0200 | From | Takashi Iwai <> | Subject | [REGRESSION 5.19.x] AMD HD-audio devices missing on 5.19 |
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Hi,
we've received regression reports about the missing HD-audio devices on AMD platforms, and this turned out to be caused by the commit 512881eacfa72c2136b27b9934b7b27504a9efc2 bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management
The details are found in openSUSE bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1202492
The problem seems to be that HD-audio (both onboard analog and HDMI) PCI devices are assigned to the same IOMMU group as AMD graphics PCI device, and once after the AMDGPU is initialized beforehand, those audio devices can't be probed since iommu_device_use_default_domain() returns -EBUSY.
I'm not sure whether it's specific to PCI bus due to the assignment logic of those IOMMU groups, or it's about the handling of the active domain assignment. In anyway, disabling IOMMU works around the problem, and passing driver_managed_dma flag to the HD-audio driver was also confirmed to work around it, too.
The problem persists with 6.0-rc1 kernel.
If you have / can give any fix patch or debug patch, let me know; I'll build test kernels and ask the reporters.
thanks,
Takashi
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