From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262019AbUL1Cjj (ORCPT ); Mon, 27 Dec 2004 21:39:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262020AbUL1Cji (ORCPT ); Mon, 27 Dec 2004 21:39:38 -0500 Received: from fmr15.intel.com ([192.55.52.69]:64473 "EHLO fmsfmr005.fm.intel.com") by vger.kernel.org with ESMTP id S262019AbUL1Cjh (ORCPT ); Mon, 27 Dec 2004 21:39:37 -0500 Subject: Re: 2.6.{9,10}: C3 not working once USB driver gets loaded (ThinkPad T40p) From: Len Brown To: Tomas Szepe Cc: linux-kernel@vger.kernel.org In-Reply-To: <20041226205053.GA27671@louise.pinerecords.com> References: <20041226205053.GA27671@louise.pinerecords.com> Content-Type: text/plain Organization: Message-Id: <1104201565.18173.36.camel@d845pe> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.3 Date: 27 Dec 2004 21:39:25 -0500 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2004-12-26 at 15:50, Tomas Szepe wrote: > Hi, > > In recent kernels (tried 2.6.9, 2.6.10), after I load the uhci_hcd > module, the processor never goes to state C3. Unloading the module > again puts things back to normal. The system is an IBM ThinkPad T40p. > > Is the USB driver setting some kinda flag in the ACPI subsystem to > achieve this behavior intentionally or is this a bug? It is not a Linux bug -- it is a system hardware architecture flaw. There is a workaround for this issue called USB Selective Suspend, which you can google and read all about. Hopefully we'll have this workaround available on Linux systems before too long. cheers, -Len