From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:53493 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752189AbcG0F5K (ORCPT ); Wed, 27 Jul 2016 01:57:10 -0400 Date: Wed, 27 Jul 2016 07:57:05 +0200 Message-ID: From: Takashi Iwai To: Vinod Koul Cc: Kuninori Morimoto , linux-renesas-soc@vger.kernel.org, Linux-ALSA , Mark Brown , Liam Girdwood , Simon Subject: Re: [alsa-devel] Question about struct snd_soc_dai() :: cpu_dai->codec In-Reply-To: <20160727032111.GY9681@localhost> References: <878twpj739.wl%kuninori.morimoto.gx@renesas.com> <20160727032111.GY9681@localhost> MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: On Wed, 27 Jul 2016 05:21:11 +0200, Vinod Koul wrote: > > On Tue, Jul 26, 2016 at 05:41:56AM +0000, Kuninori Morimoto wrote: > > > > Hi ALSA SoC > > > > My current headache is ALSA SoC's each modules (= Card/Codec/CPU/Platform) > > doesn't care about "unbind/rmmod". > > For example, if someone unbinded/rmmoded "Codec", Card or other modules > > doesn't know about it. Thus, user can continue to use this sound card, > > and kernel will be Oops. > > Are you sure about this? Have you tried removing a module? > > During card probe, asoc will hold a reference to the component. See the > calls to try_module_get(). This will prevent from unloading under normal > cases. For unloading the module, yes, it should have been prevented by managing the module refcount. However, unbinding can't be stopped by that. It's a known problem. Morimoto-san, do you see the issue really via module unloading, or is it only via unbinding? Takashi