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Message-ID: <b5271342-c804-70c1-9a81-d94efa59b203@leemhuis.info>
Date:   Mon, 19 Sep 2022 17:23:11 +0200
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Subject: Re: [REGRESSION 5.19.x] AMD HD-audio devices missing on 5.19
 #forregzbot
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From:   Thorsten Leemhuis <regressions@leemhuis.info>
To:     regressions@lists.linux.dev
Cc:     linux-kernel@vger.kernel.org
References: <874jy4cqok.wl-tiwai@suse.de>
 <c6ea56f5-05be-c9bb-4eda-a3c4a081326f@leemhuis.info>
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TWIMC: this mail is primarily send for documentation purposes and for
regzbot, my Linux kernel regression tracking bot. These mails usually
contain '#forregzbot' in the subject, to make them easy to spot and filter.

On 24.08.22 09:13, Thorsten Leemhuis wrote:

> On 22.08.22 16:12, Takashi Iwai wrote:
>>
>> 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 for the report. To be sure below issue doesn't fall through the
> cracks unnoticed, I'm adding it to regzbot, my Linux kernel regression
> tracking bot:
> 
> #regzbot introduced 512881eacfa72c2136b27b99 ^
> https://bugzilla.suse.com/show_bug.cgi?id=1202492
> #regzbot title AMD HD-audio devices missing on 5.19
> #regzbot ignore-activity

#regzbot fixed-by: 2380f1e8195ef612deea