Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760068Ab0FKJ6u (ORCPT ); Fri, 11 Jun 2010 05:58:50 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:60447 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755942Ab0FKJ6t (ORCPT ); Fri, 11 Jun 2010 05:58:49 -0400 Date: Fri, 11 Jun 2010 11:58:39 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Lothar =?iso-8859-1?Q?Wa=DFmann?= Cc: Jeremy Kerr , linux-arm-kernel@lists.infradead.org, Ben Herrenchmidt , linux-kernel@vger.kernel.org, Ben Dooks Subject: Re: [RFC,PATCH 1/2] Add a common struct clk Message-ID: <20100611095839.GC10894@pengutronix.de> References: <1275636608.606606.450179637764.0.gpush@pororo> <201006111557.12249.jeremy.kerr@canonical.com> <19473.61547.684572.647641@ipc1.ka-ro> <201006111718.47426.jeremy.kerr@canonical.com> <19474.172.742782.972629@ipc1.ka-ro> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <19474.172.742782.972629@ipc1.ka-ro> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1200 Lines: 28 On Fri, Jun 11, 2010 at 11:23:56AM +0200, Lothar Wa?mann wrote: > Hi, > > > > Using a mutex in clk_enable()/clk_disable() is a bad idea, since that > > > makes it impossible to call those functions in interrupt context. IMHO if a device generates an irq its clock should already be on. This way you don't need to enable or disable a clock in irq context. > > Do we do this at the moment? I know at least one implementation of clk_enable > > uses a mutex for locking. > > > You are probably talking about the Freescale i.MX51 kernel, that won't > even boot, if you enable CONFIG_DEBUG_KERNEL, CONFIG_DEBUG_SPINLOCK, > CONFIG_DEBUG_LOCKDEP and CONFIG_DEBUG_SPINLOCK_SLEEP. > The mutex in the clock implementation is one of the reasons. I will have a look into this later today. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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/