From owner-freebsd-current@FreeBSD.ORG Thu Sep 11 16:23:10 2008 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9CACC106566C for ; Thu, 11 Sep 2008 16:23:10 +0000 (UTC) (envelope-from julian@elischer.org) Received: from outD.internet-mail-service.net (outd.internet-mail-service.net [216.240.47.227]) by mx1.freebsd.org (Postfix) with ESMTP id 863AE8FC1A for ; Thu, 11 Sep 2008 16:23:10 +0000 (UTC) (envelope-from julian@elischer.org) Received: from idiom.com (mx0.idiom.com [216.240.32.160]) by out.internet-mail-service.net (Postfix) with ESMTP id 497502433; Thu, 11 Sep 2008 09:23:10 -0700 (PDT) Received: from julian-mac.elischer.org (localhost [127.0.0.1]) by idiom.com (Postfix) with ESMTP id 9C7922D603A; Thu, 11 Sep 2008 09:23:09 -0700 (PDT) Message-ID: <48C945EE.4070805@elischer.org> Date: Thu, 11 Sep 2008 09:23:10 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.16 (Macintosh/20080707) MIME-Version: 1.0 To: Rink Springer References: <20080819211814.6CD685B4D@mail.bitblocks.com> <48B0EA50.2090105@mawer.org> <48B3299F.5080101@vwsoft.com> <200809111013.23994.hselasky@c2i.net> <20080911103343.GH1413@rink.nu> In-Reply-To: <20080911103343.GH1413@rink.nu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Volker , Antony Mawer , current@freebsd.org, freebsd-usb@freebsd.org, Hans Petter Selasky Subject: Re: "legacy" usb stack fixes X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Sep 2008 16:23:10 -0000 Rink Springer wrote: > On Thu, Sep 11, 2008 at 10:13:22AM +0200, Hans Petter Selasky wrote: >> I also see crashes with my new stuff and the umass driver when the USB device >> is un-plugged too early. The backtraces I've got so far does not indicate a >> USB problem, though .... > > That is correct, this is a bug in CAM. More specifically, CAM does not > handle the removal of busses well. There are two possible options: > > 1) Obviously, fix CAM to handle this scenarion > DragonflyBSD seems to have a lot of fixes in this area, which I > intend to take a look at 'some day' (no thanks to $reallife...) > > 2) Create a CAM bus per USB bus > I think this is reasonable, and it makes a lot more sense than the > one-bus-per-device approach that we have now. The idea is that > every USB controller hub creates a CAM bus, and umass(4) attaches to > this bus instead of creating its own. Of course, until CAM is fixed, > detaching PCMCIA or equivalent USB cards will still cause panics, but > it would be a lot better than it is now... > This is how it was originally. There was a reason that it was changed, so make sure you look into the history to figure out what the tradeoff was. > Personally, I'd like to see option 2 implemented in the USB2 stack, as > it avoids the issue and makes a lot more sense from user perspective > (I'm probably onot the only one who gets scared by 'camcontrol devlist' > if you have a single MP3 player which advertises 2 disks :-)) > > Regards, >