From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752547AbaK0US2 (ORCPT ); Thu, 27 Nov 2014 15:18:28 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:51315 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752479AbaK0US0 convert rfc822-to-8bit (ORCPT ); Thu, 27 Nov 2014 15:18:26 -0500 From: "Rafael J. Wysocki" To: Pali =?ISO-8859-1?Q?Roh=E1r?= Cc: Greg Kroah-Hartman , Len Brown , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Missing MODALIAS in /sys/devices/system/cpu/uevent Date: Thu, 27 Nov 2014 21:39:42 +0100 Message-ID: <1716071.jpYXuFBQgb@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <201411272101.11811@pali> References: <201411272101.11811@pali> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, November 27, 2014 09:01:11 PM Pali Rohár wrote: > > --nextPart2712852.Yg3XtZvm05 > Content-Type: Text/Plain; > charset="utf-8" > Content-Transfer-Encoding: quoted-printable > > Hello, > > on 3.18-rc5 I have empty cpu uevent file, but modalias file is=20 > populated. See: > > $ cat /sys/devices/system/cpu/uevent=20 > $ cat /sys/devices/system/cpu/modalias=20 > cpu:type:x86,ven0000fam0006mod003C:feature:,0000,0001,0002,0003,0004,0005,0= > 006,0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013,0015,0016,0017,0= > 018,0019,001A,001B,001C,001D,001F,002B,0034,003A,003B,003D,0068,006B,006C,0= > 06D,006F,0070,0072,0074,0075,0076,0078,007C,007D,0080,0081,0082,0083,0084,0= > 085,0086,0087,0088,0089,008B,008C,008D,008E,008F,0091,0093,0094,0095,0096,0= > 097,0098,0099,009A,009B,009C,009D,009E,00C0,00C5,00E0,00E1,00E3,00E5,00E6,0= > 0E7,0100,0101,0102,0103,0104,0120,0121,0123,0124,0125,0127,0128,0129,012A,0= > 12B,012D,0140 > > =46or all other devices in /sys/devices/ which have modalias=20 > content there is also MODALIAS=3D line in uevent file. /sys/devices/system/cpu/ is not a device. It is a "collection of all CPUs". > Is cpu device special? Or why it is only one device which has=20 > modalias file but is missing MODALIAS=3D line in uevent file? Look into the uevent files under /sys/devices/system/cpu/cpu0/ etc. > What userspace application should use for reading modalias=20 > string? File modalias or file uevent? The cpu modalias is used to trigger loading of some CPU-specific modules upfront IIRC. So yes, it is special. My advice would be to follow udev here. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.