Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757233Ab0HDI4l (ORCPT ); Wed, 4 Aug 2010 04:56:41 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:40119 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757151Ab0HDI4i (ORCPT ); Wed, 4 Aug 2010 04:56:38 -0400 Date: Wed, 4 Aug 2010 10:09:26 +0100 From: Alan Cox To: Benjamin Herrenschmidt Cc: Dmitry Torokhov , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, David Airlie , David Miller , Fenghua Yu , Greg Kroah-Hartman , Jason Wessel , Martin Schwidefsky , Russell King , Tony Luck Subject: Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysrq ops handlers Message-ID: <20100804100926.3f24f5e5@lxorguk.ukuu.org.uk> In-Reply-To: <1280910830.1902.144.camel@pasglop> References: <20100804075602.30647.91462.stgit@localhost.localdomain> <20100804075900.30647.46910.stgit@localhost.localdomain> <1280910830.1902.144.camel@pasglop> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1040 Lines: 24 > I have a patch to drop the lock in serial_core.h, I'll post that > tomorrow hopefully, just checking if there's any objection there ? The Fundamentally - no. However the impact it has on a lot of the drivers will be significant and you'll be submitting a huge patch pile to fix up all the locking assumptions (for one it means port->tty might change across any call that ends up in sysrq) > serial drivers might need to be audited a bit to make sure they cope > with the lock being dropped and re-acquired around the sysrq call. Architecturally I think it would make more sense to add a new sysrq helper which merely sets a flag, and check that flag at the end of the IRQ when dropping the lock anyway. Otherwise it'll be a huge amount of work to even build test all those consoles. Alan -- 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/