From 888dab4b04ea8725168c6d50d0bfb8057fccca18 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Tue, 22 Sep 2026 15:42:59 +0100 Subject: [PATCH] ACPICA: Fix PCC OperationRegion command offsets ACPI 6.3, section 5.5.2.4.7.3, states that the PCC Operation Region is associated with the region of shared memory that follows the PCC signature. The generic and extended PCC shared memory layouts include the 4-byte signature at offset 0, so their raw shared memory COMMAND fields are at offsets 4 and 12 respectively. Since AML field offsets for the PCC OperationRegion are relative to the region after that signature, ACPICA must look for those COMMAND fields at OperationRegion offsets 0 and 8. Adjust the generic and master subspace command checks to use those OperationRegion-relative offsets. Otherwise writes to the COMMAND field can fail to invoke the PCC address space handler at the offset described by the PCC OperationRegion definition. Link: https://github.com/open-acpica/acpica/pull/1205 Fixes: aa6ec56b574d ("ACPICA: ACPI 6.3: add PCC operation region support for AML interpreter") Signed-off-by: Sudeep Holla [ rjw: Fixed the Fixes: tag ] Link: https://patch.msgid.link/20260922144302.3847593-2-sudeep.holla@kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpica/exfield.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/acpica/exfield.c b/drivers/acpi/acpica/exfield.c index 9a55524ed8f4..50317fe0cbd5 100644 --- a/drivers/acpi/acpica/exfield.c +++ b/drivers/acpi/acpica/exfield.c @@ -45,12 +45,13 @@ static const u8 acpi_protocol_lengths[] = { /* * The following macros determine a given offset is a COMD field. - * According to the specification, generic subspaces (types 0-2) contains a - * 2-byte COMD field at offset 4 and master subspaces (type 3) contains a 4-byte - * COMD field starting at offset 12. + * According to the specification, the PCC OperationRegion begins after + * the PCC signature. The raw shared memory COMD offsets of 4 for generic + * subspaces (types 0-2) and 12 for master subspaces (type 3) therefore + * appear at OperationRegion offsets 0 and 8. */ -#define GENERIC_SUBSPACE_COMMAND(a) (4 == a || a == 5) -#define MASTER_SUBSPACE_COMMAND(a) (12 <= a && a <= 15) +#define GENERIC_SUBSPACE_COMMAND(a) (0 == a || a == 1) +#define MASTER_SUBSPACE_COMMAND(a) (8 <= a && a <= 11) /******************************************************************************* *