linux-kernel - [RFC PATCH v4 8/8] acpi_idle: Disallow play

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Message-ID: <20241125132029.7241-9-patryk.wlazlyn@linux.intel.com>
Date: Mon, 25 Nov 2024 14:20:28 +0100
From: Patryk Wlazlyn <patryk.wlazlyn@...ux.intel.com>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	rafael.j.wysocki@...el.com,
	len.brown@...el.com,
	artem.bityutskiy@...ux.intel.com,
	dave.hansen@...ux.intel.com,
	patryk.wlazlyn@...ux.intel.com,
	peterz@...radead.org,
	tglx@...utronix.de,
	gautham.shenoy@....com
Subject: [RFC PATCH v4 8/8] acpi_idle: Disallow play_dead with FFH cstate on AMD platforms

Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@...ux.intel.com>
Suggested-by: Gautham R. Shenoy <gautham.shenoy@....com>
---
 drivers/acpi/processor_idle.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 586cc7d1d8aa..4b4ac8d55b55 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -803,7 +803,11 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 
 		state->flags = 0;
 
-		state->enter_dead = acpi_idle_play_dead;
+		/* AMD doesn't want to use mwait for play dead. */
+		bool amd_or_hygon = boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+				    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON;
+		if (!(cx->entry_method == ACPI_CSTATE_FFH && amd_or_hygon))
+			state->enter_dead = acpi_idle_play_dead;
 
 		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2)
 			drv->safe_state_index = count;
-- 
2.47.0