From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751245AbdBTWeQ (ORCPT <rfc822;w@1wt.eu>);
        Mon, 20 Feb 2017 17:34:16 -0500
Received: from mail-wm0-f68.google.com ([74.125.82.68]:36280 "EHLO
        mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750923AbdBTWeO (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 20 Feb 2017 17:34:14 -0500
Subject: Re: Bug#855183: linux-image-4.9.0-0.bpo.1-amd64: modprobe
 intel_rapl_perf stay in uninterruptible sleep
To: Thomas Gleixner <tglx@linutronix.de>,
        Ben Hutchings <ben@decadent.org.uk>
References: <20170215080829.27308.94177.reportbug@imap.fsv.cvut.cz>
 <1487292582.22520.12.camel@decadent.org.uk>
 <alpine.DEB.2.20.1702171141220.3536@nanos>
Cc: x86@kernel.org, 855183@bugs.debian.org,
        LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, Kan Liang <kan.liang@intel.com>
From: =?UTF-8?Q?Miloslav_H=c5=afla?= <miloslav.hula@gmail.com>
Message-ID: <194d53c8-0c2f-d70c-2aa4-de8af393c94f@gmail.com>
Date: Mon, 20 Feb 2017 23:34:12 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.7.1
MIME-Version: 1.0
In-Reply-To: <alpine.DEB.2.20.1702171141220.3536@nanos>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Dne 17.02.2017 v 11:47 Thomas Gleixner napsal(a):
> What's really confusing is this information from the bug report:
>
> " When I changed:
>
>   Power technology:
>   - from Energy Efficient
>   - to Custom
>
>   Energy Performance BIAS Setting:
>   - from Balanced Performance
>   - to Performance
>
>   problem disappeared. systemd-udevd starts normally, module can be
>   normally rmmod/insmod'ed now, load is 0.07."
>
> Miloslav: Is there any chance you can try a 4.10-rc8 kernel on that
> machine?

I compiled 4.10-rc8 kernel with a stock 
'/boot/config-4.9.0-0.bpo.1-amd64' config from Debian Jessie backports. 
Then I reverted BIOS settings to previous state and rebooted the server. 
Kernel and all modules loaded normally, rmmod/insmod intel_rapl_perf 
passed normally.

Then, without any BIOS change, I rebooted with stock 4.9.0-0.bpo.1-amd64 
and suprisingly, everything works, I cannot reproduce it.

My knowledge on the field of BIOS are shallow. I don't know what I can 
do to reproduce the bug now.

King redards, Miloslav