From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752339Ab3GIQgc (ORCPT ); Tue, 9 Jul 2013 12:36:32 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:42753 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751197Ab3GIQgb (ORCPT ); Tue, 9 Jul 2013 12:36:31 -0400 X-Sasl-enc: 4JuyBXDTt+gSDQJfGi2MP2MhsXTNIrsjyocRhILf6RSL 1373387789 Date: Tue, 9 Jul 2013 09:37:26 -0700 From: Greg KH To: Pavel Machek 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: <20130709163726.GA11809@kroah.com> References: <20130709012611.GA22371@amd.pavel.ucw.cz> <20130709041321.GA30555@kroah.com> <20130709094906.GA3870@amd.pavel.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130709094906.GA3870@amd.pavel.ucw.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 09, 2013 at 11:49:06AM +0200, Pavel Machek wrote: > 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 It's a module parameter, you can't control if they are present or not dynamically. > 2) operation not permitted seems like wrong error code for > operation not supported. Then what should it be? greg k-h