Re: [REGRESSION] no TPM device after "tpm_crb: Convert ACPI driver to a platform one"

> Please try the attached patch and let me know how it goes.
>
> It applies on top of the current mainline, but it may be adjusted to
> older kernels, so please let me know if you need that.

Thanks. The patch seems to be working. /dev/tpm0 and /dev/tpmrm0 are
back and a command like tpm2_get_random 16 succeeds.

> I think that these messages have been present in the kernel logs for
> quite some time, but previously they were not connected to any
> functional issues.

You are right that the messages were already present before. I see
them in the commit before "tpm_crb: Convert ACPI driver to a platform
one".

Here is what the logs say now:
acpi MSFT0101:00: Adjusting resource [mem 0xfed4000-0xfed40fff] to
[mem 0xfed40040-0xfed4103f]
tpm_crb_acpi MSFT0101:00: [Firmware Bug]: Bad ACPI memory layout

The second message was already there before too.

I'm sorry for sending multiple times the same email. I'm still learning.

On Wed, Aug 5, 2026 at 6:01 PM Rafael J. Wysocki (Intel)
<[email protected]> wrote:
>
> On Tue, Aug 4, 2026 at 9:08 PM Wysocki, Rafael J
> <[email protected]> wrote:
> >
> > Hi,
> >
> > On 8/2/2026 2:54 PM, Julien wrote:
> > > Hello,
> > >
> > > Please keep in mind this is my first time reporting a Linux kernel
> > > regression.
> > >
> > > Since commit 48fe2cddc85c ("tpm_crb: Convert ACPI driver to a platform
> > > one"), my TPM device is no longer available. Both /dev/tpm0 and
> > > /dev/tpmrm0 are missing.
> > >
> > > Log messages:
> > > platform MSFT0101:00: failed to claim resource 1: [mem
> > > 0xfed40000-0xfed40fff]
> > > acpi MSFT0101:00: platform device creation failed: -16
> > >
> > So there's no platform device for the driver to bind to.
> >
> > I think that these messages have been present in the kernel logs for
> > quite some time, but previously they were not connected to any
> > functional issues.
> >
> >
> > > I added some debug logging:
> > > ACPI resourcet[0] = [mem 0xfed40040-0xfed4103f flags 0x200]
> > > ACPI resourcet[1] = [mem 0xfed40000-0xfed40fff flags 0x200]
> > >
> > > I think the failure happens in kernel/resource.c: __insert_resource()
> > > because of the two memory regions overlapping.
> > >
> > This is quite plausible, but if that's the case, it should be fixable.
> >
> > Let me figure out something.
>
> Please try the attached patch and let me know how it goes.
>
> It applies on top of the current mainline, but it may be adjusted to
> older kernels, so please let me know if you need that.