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.


I am attaching the TPM SSDT and the SDDT defining PTTB ACPI variable address.
The value of PPTB
dd if=/dev/mem bs=1 skip=$((0x8AE5CFDC)) count=8 | hexdump -C
40 00 d4 fe 00 00 00 00

Hardware information:
  Manufacturer: Acer
  Model: Aspire ES1-572
  BIOS vendor: Insyde Corp.
  BIOS version: V1.16
  BIOS date: 09/18/2018

Thanks

#regzbot introduced: 48fe2cddc85c


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