From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x234.google.com (mail-pa0-x234.google.com [IPv6:2607:f8b0:400e:c03::234]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 268391A0089 for ; Tue, 28 Oct 2014 15:26:35 +1100 (AEDT) Received: by mail-pa0-f52.google.com with SMTP id fa1so5202933pad.11 for ; Mon, 27 Oct 2014 21:26:33 -0700 (PDT) Date: Mon, 27 Oct 2014 21:26:26 -0700 From: Nicolin Chen To: Mark Brown Subject: Re: [PATCH] ASoC: fsl_asrc: Add reg_defaults for regmap to fix kernel dump Message-ID: <20141028042603.GA5548@Asurada> References: <1414202637-18929-1-git-send-email-nicoleotsuka@gmail.com> <20141028001904.GH18557@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20141028001904.GH18557@sirena.org.uk> Cc: alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Oct 28, 2014 at 12:19:04AM +0000, Mark Brown wrote: > On Fri, Oct 24, 2014 at 07:03:57PM -0700, Nicolin Chen wrote: > > Kernel dump (WARN_ON) ocurred during system boot-up inside regmap_write(): > > > > ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 47 at kernel/locking/lockdep.c:2744 lockdep_trace_alloc+0xe8/0x108() > > Even though this may be a bug that should be fixed, I still try to send this > > patch as a quick fix (work around) since it does no harm to assign default > > values of every registers when using regcache. > > It's not a bug, it's not reasonable to default allocations to atomic and > we can't really tell what context we're in. Anything used inside a > heavily locked path should either have a default provided or arrange for > a prior write to set up the cache. I've a little trouble to understand the prior write over here. Inside my probe() there's a register_init() call which has a set of regmap_write(). And then the first regmap_write() results the dump. Does that mean this regmap_write() isn't prior write? If so, how should I do if not setting default values here -- Some IPs may have default value 0 for registers. And this would make reg_defaults tedious since there's nothing special to assign. And actually I remember I haven't seen any dump when I sent the initial patch for the whole ASRC driver but it manifested last month. I thought it might be a partially-merging issue and it would be fixed after merge window's done..... Thank you Nicolin