Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752064AbdCAGmY (ORCPT ); Wed, 1 Mar 2017 01:42:24 -0500 Received: from mail-qk0-f194.google.com ([209.85.220.194]:36350 "EHLO mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703AbdCAGmW (ORCPT ); Wed, 1 Mar 2017 01:42:22 -0500 From: Len Brown To: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Len Brown Subject: [PATCH] cpufreq: Add the "cpufreq.off=1" cmdline option Date: Tue, 28 Feb 2017 16:44:16 -0500 Message-Id: <5fd2c737538635f032e8cfa115c802145f0a9911.1488318151.git.len.brown@intel.com> X-Mailer: git-send-email 2.11.0.161.g6610af872 Reply-To: Len Brown Organization: Intel Open Source Technology Center Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1605 Lines: 47 From: Len Brown Add the "cpufreq.off=1" cmdline option. At boot-time, this allows a user to request CONFIG_CPU_FREQ=n behavior from a kernel built with CONFIG_CPU_FREQ=y. This is analogous to the existing "cpuidle.off=1" option and CONFIG_CPU_IDLE=y This capability is valuable when we need to debug end-user issues in the BIOS or in Linux. It is also convenient for enabling comparisons, which may otherwise require a new kernel, or help from BIOS SETUP, which may be buggy or unavailable. Signed-off-by: Len Brown --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ drivers/cpufreq/cpufreq.c | 1 + 2 files changed, 4 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index be7c0d9506b1..3988d2311f97 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -662,6 +662,9 @@ cpuidle.off=1 [CPU_IDLE] disable the cpuidle sub-system + cpufreq.off=1 [CPU_FREQ] + disable the cpufreq sub-system + cpu_init_udelay=N [X86] Delay for N microsec between assert and de-assert of APIC INIT to start processors. This delay occurs diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index cc475eff90b3..1c90782e3e11 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2543,4 +2543,5 @@ static int __init cpufreq_core_init(void) return 0; } +module_param(off, int, 0444); core_initcall(cpufreq_core_init); -- 2.11.0.161.g6610af872