From 92ead3c1f17f7a94f72d672024ef2b1838f3f8de Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Sat, 27 Jun 2026 17:37:30 +0100 Subject: [PATCH] hwmon: (xgene) Stop writing PCC shared memory signature ACPI specification defines the generic PCC shared memory signature as the PCC base signature ORed with the subspace ID. ACPI 6.6 added clarification that the signature is populated by the platform and verified by OSPM. The PCC mailbox controller now validates the signature when the channel is requested. Stop rewriting the signature before each command and leave the platform-populated value intact. Cc: Guenter Roeck Cc: linux-hwmon@vger.kernel.org Signed-off-by: Sudeep Holla Link: https://lore.kernel.org/r/20260627-acpi_pcc_signature-v1-2-c1b7268d4fdc@kernel.org Signed-off-by: Guenter Roeck --- drivers/hwmon/xgene-hwmon.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c index 11c5d80428cd..38b140c23c88 100644 --- a/drivers/hwmon/xgene-hwmon.c +++ b/drivers/hwmon/xgene-hwmon.c @@ -133,10 +133,6 @@ static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg) init_completion(&ctx->rd_complete); ctx->resp_pending = true; - /* Write signature for subspace */ - WRITE_ONCE(generic_comm_base->signature, - cpu_to_le32(PCC_SIGNATURE | ctx->mbox_idx)); - /* Write to the shared command region */ WRITE_ONCE(generic_comm_base->command, cpu_to_le16(MSG_TYPE(msg[0]) | PCC_CMD_GENERATE_DB_INTR));