From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261739AbTISVlG (ORCPT ); Fri, 19 Sep 2003 17:41:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261740AbTISVlG (ORCPT ); Fri, 19 Sep 2003 17:41:06 -0400 Received: from mail.kroah.org ([65.200.24.183]:8930 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S261739AbTISVlB (ORCPT ); Fri, 19 Sep 2003 17:41:01 -0400 Date: Fri, 19 Sep 2003 14:22:32 -0700 From: Greg KH To: Jan Rychter Cc: linux-kernel@vger.kernel.org Subject: Re: 2.4.22 USB problem (uhci) Message-ID: <20030919212232.GG7282@kroah.com> References: <20030919190628.GI6624@kroah.com> <20030919201751.GA7101@kroah.com> <20030919204419.GB7282@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 19, 2003 at 02:14:49PM -0700, Jan Rychter wrote: > >>>>> "Greg" == Greg KH writes: > Greg> On Fri, Sep 19, 2003 at 01:29:55PM -0700, Jan Rychter wrote: If > Greg> you want to suspend using 2.4, unload the usb drivers entirely. > Greg> That's the only safe way. > >> > >> I wasn't talking about suspending, but about processor > >> C-states. These are power states that the mobile processors enter > >> dynamically, many times a second. In my case: > > Greg> Ah, sorry. I'm getting D and C states mixed up here. > [...] > > You probably mean S-states, which are for sleep. Ugh, ok, I give up :) > >> As you can see, C3 (lowest power) is being used a lot. This makes my > >> laptop run cool. If I use usb-uhci, the processor is never able to > >> go into C3 because of DMA activity. uhci is better, because it at > >> least permits me to use C3 when there are no devices plugged in. > >> > >> And going back to the uhci problem... ? > > Greg> UHCI by design sucks massive PCI bandwidth. There is logic in > Greg> the uhci drivers that try to help this out by reducing > Greg> transactions when not much is going on, but there's only so much > Greg> we can do in software, sorry. I'm guessing that you aren't going > Greg> to be able to change this. > > Greg> Unless you go buy a ohci usb cardbus controller card :) > > Now you've confused me. > > Do your comments above apply to "uhci" or "usb-uhci"? > > Please allow me to restate the original problem: > > -- I usually use uhci instead of usb-uhci, because it is able to go > into "suspend mode" when no devices are plugged, which allows the > CPU to enter C3 states, > > -- usb-uhci eats CPU power by keeping it in C2 constantly because of > busmastering DMA activity, therefore being much less useful, > > -- uhci generally works for me just fine, but breaks in one particular > case, when removing the device causes a strange message to be > printed and the system being unable to use the C3 states again, > until uhci is unloaded and reloaded back again. > > Just as a reminder, this message is: > > uhci.c: efe0: host controller halted. very bad > > I hope if the message says "very bad", then this is something that can > be fixed. I was therefore reporting a problem with "uhci" and kindly > asking for help. Ok, sorry for the confusion. No I don't know of a fix for this problem, but one just went into the 2.6 kernel tree for the uhci-hcd driver that you might want to take a look at that fixed a problem almost exactly like this. thanks, greg k-h