From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH 05/14] ALSA: pci: Remove superfluous snd_pcm_suspend*() calls Date: Wed, 16 Jan 2019 16:52:53 +0100 Message-ID: References: <20190115162155.6308-1-tiwai@suse.de> <20190115162155.6308-6-tiwai@suse.de> <20190116155027.GB7186@sirena.org.uk> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id B83D02666B3 for ; Wed, 16 Jan 2019 16:52:54 +0100 (CET) In-Reply-To: <20190116155027.GB7186@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: Libin Yang , alsa-devel@alsa-project.org, Mengdong Lin , Keyon Jie , Pierre-Louis Bossart , liam.r.girdwood@linux.intel.com List-Id: alsa-devel@alsa-project.org On Wed, 16 Jan 2019 16:50:27 +0100, Mark Brown wrote: > > On Tue, Jan 15, 2019 at 09:42:09PM +0100, Takashi Iwai wrote: > > > The last one has prepare and complete callbacks in addition to the > > other standard PM calls. And tm2_pm_preapre() stops sysclk and > > complete() starts sysclk. I don't understand why these are needed in > > prepare and resume. Can anyone explain? > > AFAICT it's just making sure that they're available ASAP so they look > always on to the rest of the system. Well, but PM prepare is called before PM suspend call. And the whole ASoC suspend procedure (including PCM suspend, etc) is performed in the PM suspend callback; i.e. we stop sysclk before doing anything else... Takashi