Re: [REGRESSION] AMDISP failure with kernel v7.0-rc2 due to Commit: 02c057ddefef5

[Nirujogi, Pratap]

On 3/6/2026 7:45 AM, Mario Limonciello wrote:
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>
> On 3/6/26 6:01 AM, Rafael J. Wysocki wrote:
> > On Fri, Mar 6, 2026 at 1:35 AM Mario Limonciello (AMD) (kernel.org)
> > <superm1@xxxxxxxxxx> wrote:
> > > On 3/5/2026 5:11 PM, Nirujogi, Pratap wrote:
> > > > Hi Rafael,
> > > >
> > > > In kernel version 7.0-rc2, the AMDISP device reports the following
> > > > errors when created via mfd_add_hotplug_devices.
> > > >
> > > > [    5.236645] ACPI: video: Video Device [GFX0] (multi-head: yes  rom:
> > > > no  post: no)
> > > > [    5.236744] input: Video Bus as /devices/
> > > > pci0000:00/0000:00:08.1/0000:c3:00.0/amd_isp_capture.1.auto/input/ 
> > > > input21
> > > > [    5.236779] acpi device:14: Error installing notify handler
> > > > [    5.236782] acpi device:15: Error installing notify handler
> > > > [    5.236783] acpi device:16: Error installing notify handler
> > > > [    5.236784] acpi device:17: Error installing notify handler
> > > > [    5.236785] acpi device:18: Error installing notify handler
> > > > [    5.236786] acpi device:19: Error installing notify handler
> > > > [    5.236786] acpi device:1a: Error installing notify handler
> > > > [    5.236787] acpi device:1b: Error installing notify handler
> > > > [    5.236788] acpi device:1c: Error installing notify handler
> > > >
> > > > These failures indicate AMDISP device is incorrectly detected as ACPI
> > > > Video device while it is not.
> > > >
> > > > The seems like a regression caused by the change that converts the ACPI
> > > > video device to a platform device (commit: 02c057ddefef5).
> > > >
> > > > Issue is not observed in 6.19-rc6, and also when this change is 
> > > > reverted
> > > > in 7.0-rc2.
> > > >
> > > > I really appreciate your inputs on addressing this issue and helping us
> > > > make progress on 7.0 rc2.
> > > >
> > > > Steps followed to reproduce the issue:
> > > >
> > > > 1. Apply AMDISP v9 patch series [1] on top of kernel v7.0-rc2
> > > > 2. Add NULL check for “dev->type” in isp_genpd_add_device() [2] (to
> > > > avoid kernel panic found in v7.0-rc2)
> > > > 3. Build kernel with:
> > > >       - CONFIG_AMD_ISP_PLATFORM=y
> > > >       - CONFIG_VIDEO_AMD_ISP4_CAPTURE=m
> > > > 4. Install kernel on AMDISP supported system (HP ZBook Ultra G1a)
> > > > 5. Boot system to see the failures
> > > >
> > > > [1] https://lore.kernel.org/all/20260302073020.148277-1-Bin.Du@xxxxxxx/
> > > > [2] https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/amd/
> > > > amdgpu/isp_v4_1_1.c#L132
> > > >
> > > > Thanks,
> > > > Pratap
> > >
> > > It's a bit weird to see it even probe in this path in the first place.
> > > acpi_video_bus_probe() getting called with the mfd device doesn't seem
> > > right to me.
> > >
> > > I wonder if it's because ISP is an MFD device of GPU (and thus LNXVIDEO
> > > ends up matching).
> > >
> > > Would a sensible solution be to reject mfd device types in
> > > acpi_video_bus_probe()?
> >
> > Every platform device with LNXVIDEO in the device ID list will be
> > matched and so probed.
> >
> > I'm wondering how those devices get that ID though.
>
> Yeah me too.  I was surprised an MFD device got it.
>
> Pratap - can you figure this out before we go too far in this path?
yes, MFD child devices in this case have the device ID as that of parent 
(GPU) i.e. LNXVIDEO. Its because when no acpi_match is specified, the 
MFD child devices are inheriting the parent's ACPI companion device and 
this is resulting in having the same parent's ACPI device ID.

device_set_node(&pdev->dev, acpi_fwnode_handle(adev ?: parent));
https://github.com/torvalds/linux/blob/master/drivers/mfd/mfd-core.c#L91

> If they really shouldn't have LNXVIDEO fixing that may be a better 
> solution.
AMD ISP related MFD devices are using the same LNXVIDEO device ID even 
on 6.19-rc4, no issues observed earlier. I can confirm automatic AMD ISP 
device probe works and also camera works on 7.0-rc2 if I avoid 
inheriting ACPI companion of the parent (GPU) in the mfd-core.c

// device_set_node(&pdev->dev, acpi_fwnode_handle(adev ?: parent));
https://github.com/torvalds/linux/blob/master/drivers/mfd/mfd-core.c#L91

But why this is an issue on 7.0-rc2 while it works on 6.19-rc4 needs to 
be root caused.

> > Also, is this really a mainline regression?  AMDISP patches are not in
> > the mainline, no?
>
> The amdgpu half of it is mainline, the other half is still on the lists.