The attached patch is a one-line change to linux-pm 5.16-rc8.

The patch simply adds ACPI_SIG_CEDT to table_sigs[] in 
"drivers/acpi/tables.c".

Presently, CXL code isn't able to make use of the CEDT table. Subsequent 
to the change, the CEDT table can be used.

If a developer plans to use the CEDT table to program the CXL ports, 
this change is needed. Otherwise, it isn't expected to make a difference.

If this should go to linux-acpi as opposed to linux-pm, please excuse 
the error.

Regards, Robert (the Old Coder)

Subject: Make ACPI subsystem provide CEDT table
Author: Robert Kiraly <me@boldcoder.com>

This  is a  one-line patch to the "linux-pm" ACPI subsystem 5.16-
rc8.

The patch simply adds ACPI_SIG_CEDT to table_sigs[] in  "drivers/
acpi/tables.c".

Presently, CXL  code  isn't able to make use of the  CEDT  table.
Subsequent to the change, the CEDT table can be used.

If  a developer  plans to use the CEDT table to  program  the CXL
ports,  this change is needed.  Otherwise,  it isn't  expected to
make a difference.

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 71419eb16e09..3cccd7a12f22 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -500,7 +500,7 @@ static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst = {
 	ACPI_SIG_WDDT, ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT,
 	ACPI_SIG_PSDT, ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT,
 	ACPI_SIG_IORT, ACPI_SIG_NFIT, ACPI_SIG_HMAT, ACPI_SIG_PPTT,
-	ACPI_SIG_NHLT };
+	ACPI_SIG_NHLT, ACPI_SIG_CEDT };
 
 #define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
 
=== end of patch ====

On Wed, Jan 12, 2022 at 6:20 AM Robert Kiraly <me@boldcoder.com> wrote:
>
> The attached patch is a one-line change to linux-pm 5.16-rc8.
>
> The patch simply adds ACPI_SIG_CEDT to table_sigs[] in
> "drivers/acpi/tables.c".
>
> Presently, CXL code isn't able to make use of the CEDT table. Subsequent
> to the change, the CEDT table can be used.
>
> If a developer plans to use the CEDT table to program the CXL ports,
> this change is needed. Otherwise, it isn't expected to make a difference.
>
> If this should go to linux-acpi as opposed to linux-pm, please excuse
> the error.

Yes, it should, but please see this PR too:

https://patchwork.kernel.org/project/linux-acpi/patch/CAPcyv4j0NfC4RKr=VU6yUKrqVRKdAer9YeSezRctpp-k31iAzA@mail.gmail.com/