From: Mario Limonciello <superm1@kernel.org>
To: Mark Somerville <mark@qpok.net>, stable@vger.kernel.org
Cc: regressions@lists.linux.dev,
"Alex Deucher" <alexander.deucher@amd.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Christian König" <christian.koenig@amd.com>,
"Xinhui Pan" <Xinhui.Pan@amd.com>
Subject: Re: [REGRESSION] Unable to pass AMD RX 6400 GPU via VFIO
Date: Fri, 20 Mar 2026 06:42:41 -0500 [thread overview]
Message-ID: <1ce6b64b-47e7-4e73-a73f-58bf5f5202b1@kernel.org> (raw)
In-Reply-To: <1be114e1130ca59ee91fc5a73aaf43a912d408ea@qpok.net>
On 3/20/26 4:28 AM, Mark Somerville wrote:
> Hello maintainers!
>
> I run Debian 13 stable (6.12 kernel) and have encountered a regression.
>
> My machine has three GPUs, the iGPU that is part of my 7950X and two dGPUs - one NVIDIA 3090 and one AMD RX 6400. I use the iGPU for the host and only use the two dGPUs with virtual machines via VFIO with libvirt.
>
> Although I have specified kernel parameters vfio_pci.ids for the GPUs, I have not blacklisted the amdgpu driver so that the host iGPU can operate. Previously, starting a VM with the RX 6400 dGPU assigned to it (via VFIO) would work fine. However, doing this with more recent stable kernels causes the machine to hang immediately (and then, ultimately, reset after a while - ~30s). No errors are logged, at least as things are configured just now.
>
> I can reliably reproduce this crash and a bisection revealed the commit that introducted the problem: 8140ac7c55e75093a01c6110a2c4025fe7177c57.
>
> This is fixed in the mainline kernel, I have tested and verified my RX 6400 is working with VFIO under 7.0-rc4.
>
> I *think* this is still present in the 6.12.y branch but a second (currently ongoing) regression is preventing me checking this on the latest and greatest 6.12 release right now.
>
> Working: 6.12.63
> Regressed: 6.12.69
> Working: 7.0-rc4
>
> #regzbot introduced: 8140ac7c55e75093a01c6110a2c4025fe7177c57
If you bisected to 8140ac7c55e75093a01c6110a2c4025fe7177c57, try adding
f7afda7fcd169a9168695247d07ad94cf7b9798f.
next prev parent reply other threads:[~2026-03-20 11:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-20 9:28 [REGRESSION] Unable to pass AMD RX 6400 GPU via VFIO Mark Somerville
2026-03-20 11:42 ` Thorsten Leemhuis
2026-03-20 12:34 ` Greg Kroah-Hartman
2026-03-20 11:42 ` Mario Limonciello [this message]
2026-03-20 13:33 ` Mark Somerville
2026-03-20 13:51 ` Mario Limonciello (AMD) (kernel.org)
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