Re: [PATCH] kernel: resourse: Add conditional handling for ACPI device

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, Oct 23, 2025 at 04:04:55PM +0800, Szuying Chen wrote:
> On Sun, Oct 19, 2025 at 03:07AM, Andy Shevchenko wrote:
> > On Fri, Oct 17, 2025 at 10:35:31AM +0800, Szuying Chen wrote:
> > > To avoid address conflicts and related errors, specific checks for
> > > the ACPI device "AMDIF031" should be bypassed.
> > 
> > TL;DR: NAK.
> > 
> > No, this is not how we should do the quirks (besides the use of CamelCase).
> > Also, please provide more info why firmware may not be fixed properly at
> > the same time, so we won't need this on an updated version?
> 
> The ACPI device AMDIF031 is a virtual (non-PCI) device located on the PCI
> upstream port. Its memory resource is assigned by the BIOS within the bridge
> windows of the PCI upstream port.
> 
> When the kernel creates ACPI/AMDIF031 and verifies memory resources, it may
> detect an address conflict between AMDIF031 and the PCI upstream port. The
> kernel then attempts to reassign resources for the PCI upstream port tree,
> causing AMDIF031's memory resource to fall outside the bridge windows. This
> makes the device inaccessible.
> 
> To prevent this and allow AMDIF031 to use the BIOS-assigned memory range,
> skip resource reallocation when an address conflict is detected for this 
> device.

We have such devices in many platforms, older ones use MFD framework with
specific flag set, you may check how it's done there. But for this change is
definitely NAK, take your time to find proper solution (see above for the
hint).

-- 
With Best Regards,
Andy Shevchenko