From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264228AbUE3R0U (ORCPT ); Sun, 30 May 2004 13:26:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264253AbUE3R0T (ORCPT ); Sun, 30 May 2004 13:26:19 -0400 Received: from smtp810.mail.sc5.yahoo.com ([66.163.170.80]:12887 "HELO smtp810.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S264228AbUE3R0K (ORCPT ); Sun, 30 May 2004 13:26:10 -0400 From: Dmitry Torokhov To: linux-kernel@vger.kernel.org Subject: Re: keyboard problem with 2.6.6 Date: Sun, 30 May 2004 12:26:05 -0500 User-Agent: KMail/1.6.2 Cc: Sau Dan Lee , Vojtech Pavlik , Giuseppe Bilotta , Tuukka Toivonen References: <20040530121606.GA1496@ucw.cz> In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="big5" Content-Transfer-Encoding: 7bit Message-Id: <200405301226.05596.dtor_core@ameritech.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sunday 30 May 2004 07:40 am, Sau Dan Lee wrote: > >>>>> "Vojtech" == Vojtech Pavlik writes: > > >> Where it is now possible to move it out of kernel space WITHOUT > >> performance problems, why not move it out? > > Vojtech> Because it just works. > > Vojtech> 1) Upgrading the kernel will make your keyboard stop > Vojtech> working. Noone has installed your userspace daemons on > Vojtech> the system. > > Many people has already fallen into this trap with YOUR input system: > they didn't know they had to enable the 'i8042' and 'atkbd' features, > or they did but made them modules and didn't have any clue to insmod > them in the bootup scripts. This was in development series (2.5) and was resolved by the time 2.6 came out so I really do not think it's a valid complaint. > Vojtech> 2) The keyboard (and other input devices, so that you > Vojtech> don't complain about limiting this to the keyboard) > Vojtech> should work without requiring userspace to be running. > > Is a network interface an input device? Or do you just mean HID? > > USB devices (including USB keyboards and mice) require hot-plug (or > similar mechanisms) to load the corresponding modules before they can > work. Both /sbin/hotplug and /sbin/modprobe on my system are > userspace programs. > > > Vojtech> And, it works just fine in the kernel, doesn't take up > Vojtech> any more space than as a program, so why to move it out? > > To leave more *swappable* RAM to userspace. > On average it will take much more considering that you better have your keyboard daemon linked statically and residing.. umm.. initrd? initramfs? as you want your keyboard working very early. > >> Yeah. At what rate are they arriving? 1200baud. Let's say > >> that' 9600bps. So, 1200 bytes per second. 1 byte in every 833 > >> microseconds. How come a processor at 33MHz (0.030 > >> microseconds per clock cycle) cannot cope with that? Assuming > >> that the processing of the data plus context switching plus > >> other overhead taks 1000 microseconds, that still shouldn't be > >> felt by a HUMAN user. Who has a reaction time of less than 100 > >> _milli_seconds? > > Vojtech> Can you say swap? > > Can you say mlock()? > I though you wanted the thing to be swapped out? Btw, what are you going to mlock? Entirety of glibc? -- Dmitry