Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261587AbTIUAPk (ORCPT ); Sat, 20 Sep 2003 20:15:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261602AbTIUAPk (ORCPT ); Sat, 20 Sep 2003 20:15:40 -0400 Received: from main.gmane.org ([80.91.224.249]:26271 "EHLO main.gmane.org") by vger.kernel.org with ESMTP id S261587AbTIUAPj (ORCPT ); Sat, 20 Sep 2003 20:15:39 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Jan Rychter Subject: Re: 2.4.22 USB problem (uhci) Date: Sat, 20 Sep 2003 17:15:57 -0700 Message-ID: References: <20030919190628.GI6624@kroah.com> <20030919201751.GA7101@kroah.com> <20030919204419.GB7282@kroah.com> <20030919212232.GG7282@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Complaints-To: usenet@sea.gmane.org X-Spammers-Please: blackholeme@rychter.com User-Agent: Gnus/5.1003 (Gnus v5.10.3) XEmacs/21.4 (Rational FORTRAN, linux) Cancel-Lock: sha1:aRCwEayRvts4fus6qdIejfkUCxs= Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2176 Lines: 50 >>>>> "Jan" == Jan Rychter : >>>>> "Greg" == Greg KH writes: Jan> [...] > 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. Greg> Ok, sorry for the confusion. No I don't know of a fix for this Greg> problem, but one just went into the 2.6 kernel tree for the Greg> uhci-hcd driver that you might want to take a look at that fixed Greg> a problem almost exactly like this. Jan> Greg, Jan> I've looked at uhci.c, the message comes from line 2461, in Jan> uhci_interrupt. But there is no chance I will be able to fix it Jan> without first understanding thoroughly how uhci.c works. Jan> So I guess this goes into my "unfixed Linux bugs" bin. I've just realized that some people may not know why the above uhci bug is a problem. Having done some measurements and calculations, the above uhci bug translates into a shortened battery life: 20 minutes less for the laptop I've been testing on. You get 1h30 instead of 1h50 you would normally get if uhci would work correctly. That's like having only 84% of your battery available to start with. --J. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/