Return-path: Received: from mail.gmx.net ([213.165.64.20]:39711 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754426AbZKCVAP (ORCPT ); Tue, 3 Nov 2009 16:00:15 -0500 Message-ID: <4AF095C3.5020409@gmx.net> Date: Tue, 03 Nov 2009 21:42:43 +0100 From: Frank Schaefer MIME-Version: 1.0 To: Alan Stern CC: linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org Subject: Re: [PATCH] ar9170usb: add mode-switching for AVM Fritz!WLAN USB N devices in cdrom mode References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: Alan Stern schrieb: > On Mon, 2 Nov 2009, Dan Williams wrote >> In userspace, usb_modeswitch is the place to put all this logic. Then >> you tie it together with udev rules using some bubble-gum and duct-tape, >> and maybe it works. Of course, there's massive duplication of data >> between usb_modeswitch and the kernel drivers, because the there's >> simply no communication between the two. >> > The only reason for this "massive" duplication is that nobody has > bothered to remove from the kernel the parts that usb_modeswitch can > handle. Adding yet more switching code into the kernel, thereby > _increasing_ the amount of duplication, seems like a bad idea. > Or the other way around ;) . Of course, we all don't want any duplicate code. We need a kernelspace OR a userspace-solution. But we should make pragmatic and device-(group-)specific decisions. The hardware itself and the context in which it is used (=> switch-policy) are too different. ... > ... Jobs that can be handled > in userspace _should_ be handled there. > > Alan Stern > Basically, I have no problem to agree here. But what's the price we pay for this solution(s) in this case (and most other devices with windows-driver-disc-mode) ? You should not ignore the problems coming-up with the discussed userspace-solutions. This is not ONLY about technical aspects. We already discussed usability and maintanance. Think about the whole product, not only the kernel-part. Then, please, make a list of ALL pros and cons a make a pragmatic decision. Frank