From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753072Ab3GIJtL (ORCPT ); Tue, 9 Jul 2013 05:49:11 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:34989 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751960Ab3GIJtI (ORCPT ); Tue, 9 Jul 2013 05:49:08 -0400 Date: Tue, 9 Jul 2013 11:49:06 +0200 From: Pavel Machek To: Greg KH Cc: kernel list , joe.lawrence@stratus.com, myron.stowe@redhat.com, bhelgaas@google.com Subject: Re: /sys/module/pcie_aspm/parameters/policy not writable? Message-ID: <20130709094906.GA3870@amd.pavel.ucw.cz> References: <20130709012611.GA22371@amd.pavel.ucw.cz> <20130709041321.GA30555@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130709041321.GA30555@kroah.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2013-07-08 21:13:21, Greg KH wrote: > On Tue, Jul 09, 2013 at 03:26:11AM +0200, Pavel Machek wrote: > > Hi! > > > > My thinkpad has rather high ping latencies... and perhaps it is due to > > PCIE ASPM. > > Why would that be the problem? The odds that the PCIE bus is the issue > seems strange to me. Aha: I guess that's why the file is not writable: pavel@amd:~$ dmesg | grep -i aspm ACPI FADT declares the system doesn't support PCIe ASPM, so disable it e1000e 0000:02:00.0: Disabling ASPM L0s L1 pavel@amd:~$ cat /sys/module/pcie_aspm/parameters/policy [default] performance powersave pavel@amd:~$ root@amd:~# echo -n performance > /sys/module/pcie_aspm/parameters/policy -su: echo: write error: Operation not permitted root@amd:~# But: 1) it should not list unavailable options 2) operation not permitted seems like wrong error code for operation not supported. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html