From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT Date: Wed, 20 Jul 2016 01:38:56 +0200 Message-ID: References: <1468971284-17686-1-git-send-email-srinivas.pandruvada@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:33694 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752024AbcGSXjL (ORCPT ); Tue, 19 Jul 2016 19:39:11 -0400 Received: by mail-wm0-f67.google.com with SMTP id o80so4533049wme.0 for ; Tue, 19 Jul 2016 16:38:58 -0700 (PDT) In-Reply-To: <1468971284-17686-1-git-send-email-srinivas.pandruvada@linux.intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Srinivas Pandruvada Cc: "Rafael J. Wysocki" , Linux PM , spandruv On Wed, Jul 20, 2016 at 1:34 AM, Srinivas Pandruvada wrote: > From: spandruv > > The MSR MSR_HWP_INTERRUPT is valid only when CPUID.06H:EAX[8] = 1, so > check for feature before accessing this MSR. > > Signed-off-by: spandruv Do you really want this in the S-o-b tag? > --- > drivers/cpufreq/intel_pstate.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 2fe9af1..712afbd 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -822,8 +822,10 @@ static void __init intel_pstate_sysfs_expose_params(void) > > static void intel_pstate_hwp_enable(struct cpudata *cpudata) > { > + > /* First disable HWP notification interrupt as we don't process them */ > - wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x00); > + if (static_cpu_has(X86_FEATURE_HWP_NOTIFY)) > + wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x00); > > wrmsrl_on_cpu(cpudata->cpu, MSR_PM_ENABLE, 0x1); > } > --