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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linux ACPI <linux-acpi@vger.kernel.org>,
	Len Brown <len.brown@intel.com>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Len Brown <lenb@kernel.org>
Subject: [PATCH v1 09/10] intel_idle: Add module parameter to prevent ACPI _CST from being used
Date: Fri, 13 Dec 2019 10:24:58 +0100	[thread overview]
Message-ID: <4991900.sFTjH42vUX@kreacher> (raw)
In-Reply-To: <3950312.2WmFeOdZGY@kreacher>

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

Add a new module parameter called "no_acpi" to the intel_idle driver
to allow the driver to be prevented from using ACPI _CST via kernel
command line.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

No changes from the RFC version.

---
 drivers/idle/intel_idle.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index a072b84d9595..26fe383bb921 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -1138,6 +1138,10 @@ static bool intel_idle_max_cstate_reached(int cstate)
 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
 #include <acpi/processor.h>
 
+static bool no_acpi __read_mostly;
+module_param(no_acpi, bool, 0444);
+MODULE_PARM_DESC(no_acpi, "Do not use ACPI _CST for building the idle states list");
+
 static struct acpi_processor_power acpi_state_table;
 
 /**
@@ -1167,6 +1171,11 @@ static bool intel_idle_acpi_cst_extract(void)
 {
 	unsigned int cpu;
 
+	if (no_acpi) {
+		pr_debug("Not allowed to use ACPI _CST\n");
+		return false;
+	}
+
 	for_each_possible_cpu(cpu) {
 		struct acpi_processor *pr = per_cpu(processors, cpu);
 
-- 
2.16.4






  parent reply	other threads:[~2019-12-13  9:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-13  9:09 [PATCH v1 00/10] cpuidle: intel_idle: Use ACPI _CST to get idle states information Rafael J. Wysocki
2019-12-13  9:11 ` [PATCH v1 01/10] ACPI: processor: Export function to claim _CST control Rafael J. Wysocki
2019-12-13  9:12 ` [PATCH v1 02/10] ACPI: processor: Introduce acpi_processor_evaluate_cst() Rafael J. Wysocki
2019-12-13  9:14 ` [PATCH v1 03/10] ACPI: processor: Clean up acpi_processor_evaluate_cst() Rafael J. Wysocki
2019-12-13  9:15 ` [PATCH v1 04/10] ACPI: processor: Export acpi_processor_evaluate_cst() Rafael J. Wysocki
2019-12-13  9:16 ` [PATCH v1 05/10] intel_idle: Refactor intel_idle_cpuidle_driver_init() Rafael J. Wysocki
2019-12-13  9:20 ` [PATCH v1 06/10] intel_idle: Use ACPI _CST for processor models without C-state tables Rafael J. Wysocki
2019-12-13  9:22 ` [PATCH v1 07/10] cpuidle: Allow idle states to be disabled by default Rafael J. Wysocki
2019-12-13  9:24 ` [PATCH v1 08/10] intel_idle: Allow ACPI _CST to be used for selected known processors Rafael J. Wysocki
2019-12-13  9:24 ` Rafael J. Wysocki [this message]
2019-12-13  9:27 ` [PATCH v1 10/10] intel_idle: Use ACPI _CST on server systems Rafael J. Wysocki

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