Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261925AbVECXrl (ORCPT ); Tue, 3 May 2005 19:47:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261926AbVECXrk (ORCPT ); Tue, 3 May 2005 19:47:40 -0400 Received: from gate.crashing.org ([63.228.1.57]:1463 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S261925AbVECXr2 (ORCPT ); Tue, 3 May 2005 19:47:28 -0400 Subject: Re: [PATCH] fix __mod_timer vs __run_timers deadlock. From: Benjamin Herrenschmidt To: "David S. Miller" Cc: Paul Mackerras , jk@blackdown.de, akpm@osdl.org, oleg@tv-sign.ru, linux-kernel@vger.kernel.org, maneesh@in.ibm.com In-Reply-To: <20050503115103.7461ae5e.davem@davemloft.net> References: <42748B75.D6CBF829@tv-sign.ru> <20050501023149.6908c573.akpm@osdl.org> <87vf61kztb.fsf@blackdown.de> <1115079230.6155.35.camel@gaston> <873bt5xf9v.fsf@blackdown.de> <17014.59016.336852.31119@cargo.ozlabs.ibm.com> <20050503115103.7461ae5e.davem@davemloft.net> Content-Type: text/plain Date: Wed, 04 May 2005 09:44:53 +1000 Message-Id: <1115163893.7568.49.camel@gaston> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 38 On Tue, 2005-05-03 at 11:51 -0700, David S. Miller wrote: > On Tue, 3 May 2005 12:48:40 +1000 > Paul Mackerras wrote: > > > Juergen Kreileder writes: > > > > > BTW, xmon doesn't work for me. 'echo x > /proc/sysrq-trigger' gives > > > me a :mon> prompt but I can't enter any commands. > > > > We don't have polled interrupts-off input methods for USB keyboards. > > There is nothing in the USB nor INPUT layers really blocking an > implementation of this BTW. > > I need this on Sparc64 as well, so that PROM command line input > works after booting with USB keyboards. Nothing prevents it ? well, I wouldn't be that optimistic :) The USB stuff is a bit complex, it inlcudes doing DMAs, so manipulating the iommu, dealing with URB queues (and thus allocating/releasing them) etc... and especially in the context of xmon, that mean letting the driver do a lot of these at any time whatever state the system is... So it's possible, but will probably be difficult and not very reliable. An alternative is to take over the OHCI chip completely and implement a micro-stack that only does interrupt pipe polling and hard decodes kbd data based on a standard boot protocol layout... Handing the controller back to normal USB operations may prove a bit difficult here though. Ben. - 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/