Thread by @NikolajSchlej

Annual "new somewhat interesting stuff in ACPI/UEFI/PI specs updates" thread, let's go. PI 1.8 is not published yet, so I'll add it when it be ready.🧵

[ACPI 6.4] A new ACPI system descriptor table 'SVKL', aka "Storage Volume Key Data table in the Intel Trusted Domain Extensions". Described and defined here among other things related to Intel TDX: software.intel.com/content/dam/de…

[ACPI 6.4] A new ACPI system descriptor table 'MPAM', aka "Arm Memory Partitioning And Monitoring". Should be defined and described in Arm DEN0065 document, but it's still in beta and not yet publicly available. This presentation has some hints: static.linaro.org/connect/lvc20/…

[ACPI 6.4] A new ACPI system descriptor table 'AEST' aka "Arm Error Source Table". Defined and described in Arm DEN0085 document: developer.arm.com/documentation/…

[ACPI 6.4] A new ACPI system descriptor table 'PRMT' aka "Platform Runtime Mechanism Table". Defined and described in PRM spec here: uefi.org/sites/default/…
A better replacement for dangerous and unpredictable SMM handlers, it would be *great* if IBVs and OEMs start using it.

[ACPI 6.4] A new ACPI system descriptor table 'PTDT' aka "Platform Telemetry Data Table" is mentioned in the changelog, but not defined in the document itself. CC @vincentzimmer for either adding the definition or removing it from changelog in errata A.

[ACPI 6.4] A new ACPI system descriptor table 'RGRT', aka "Regulatory Graphics Resource Table". Described and defined here: microsoft.github.io/mu/dyn/mu_plus…
"A PNG with the regulatory info. Could include FCC id, UL, Model number, or CMIIT ID, to be picked up by the OS later to display."

[ACPI 6.4] A new ACPI system descriptor table 'CEDT', aka "CXL Early Discovery Table". Defined in CXL 2.0 specification that requires registration to get access to. If you do not want to register, there's a definition in this UEFI Plugfest presentation: uefi.org/sites/default/…

[ACPI 6.4] A new ACPI system descriptor table 'BDAT', aka "BIOS Data ACPI Table". Described and defined here: uefi.org/sites/default/…
The table provides access to the training/margining data generated by PRC to the tools in OS: …70300198708936b4e.ssl.cf1.rackcdn.com/images/35a8342…

[ACPI 6.4] 'DPPT' aka "DMA Protection Policy Table" reference added in ACPI 6.2 is now gone from the spec. There were no public documents defining it anyway, and I'm glad to see unused things removed.

[ACPI 6.4] Battery Charge Limiting capability is added to Battery Management chapter.

[ACPI 6.4] PCI Bar Target (Generic Address Structure Space with ID 0x06) is now defined in the spec.

[ACPI 6.4] A new ACPI system descriptor table 'PHAT', aka "Platform Health Assessment Table". Defined and described in the spec itself.

[ACPI 6.4] A new MADT entry type 0x10 - "Multiprocessor Wakeup Structure". Defined and described in the spec itself.

[ACPI 6.4] Added a previously missing definition of "ACPI_NAMESPACE_DEVICE based Secure Device Structure".

[ACPI 6.4] Added two new ACPI Device IDs: ACPI0015 for "USB4 Host Interface Device", ACPI0016 for "Compute Express Link Host Bridge".

[ACPI 6.4] Added definition of _OSC for USB4 devices.

[ACPI 6.4] Added definition of "Camera Serial Interface (CSI-2) Connection Resource Descriptor".

[ACPI 6.4] Added definition of optional ACPI method '_CBR', aka " CXL Host Bridge Register Info".

[ACPI 6.4] Added previously missing table to "Power, Performance, and Throttling State Dependencies" chapter.

[ACPI 6.4] PCCT table description extended to include "HW Registers based Communications Subspace Structure (Type 5)".

[ACPI 6.4] New ASL macro "CSI2Bus".

[ACPI 6.4] Already deprecated ASL "Processor" operator is removed for good.

That'll be all for ACPI 6.4, folks. There are definitely some minor changes that I've missed, and some other non-minor changes are hard to describe in a tweet (like ones in "Control Method Batteries" chapter). Will do UEFI 2.9 tomorrow. 🧵🔚