From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH] PCM: snd_pcm_dmix_drain() maybe blocked after suspend and resume Date: Tue, 09 Jun 2015 07:27:24 +0200 Message-ID: References: <1433756291-22999-1-git-send-email-shengjiu.wang@freescale.com> <20150609023539.GA3277@shlinux2> 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 mx2.suse.de (cantor2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id 8E64E264F33 for ; Tue, 9 Jun 2015 07:27:25 +0200 (CEST) In-Reply-To: <20150609023539.GA3277@shlinux2> 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: Shengjiu Wang Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org At Tue, 9 Jun 2015 10:35:41 +0800, Shengjiu Wang wrote: > > On Mon, Jun 08, 2015 at 01:31:41PM +0200, Takashi Iwai wrote: > > At Mon, 8 Jun 2015 17:38:11 +0800, > > Shengjiu Wang wrote: > > > > > > After suspend and resume, the alsa driver is stopped. But if alsa-lib run > > > into snd_pcm_dmix_drain(), it need to wait avail >= pcm->stop_threshold, > > > otherwise, it will not exit the loop, so finally it is blocked at poll() of > > > snd_pcm_wait_nocheck(pcm, -1). > > > This patch is to add state check after snd_pcm_wait_nocheck(pcm, -1), if > > > the state is SND_PCM_STATE_SUSPENDED, then return error. > > > > > > Signed-off-by: Shengjiu Wang > > > --- > > > src/pcm/pcm_dmix.c | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c > > > index babde6a..0cc318e 100644 > > > --- a/src/pcm/pcm_dmix.c > > > +++ b/src/pcm/pcm_dmix.c > > > @@ -647,6 +647,12 @@ static int snd_pcm_dmix_drain(snd_pcm_t *pcm) > > > if (dmix->state == SND_PCM_STATE_DRAINING) { > > > snd_pcm_dmix_sync_area(pcm); > > > snd_pcm_wait_nocheck(pcm, -1); > > > + switch (snd_pcm_state(pcm)) { > > > > It's better (shorter) to call snd_pcm_state(dmix->spcm) in this case. > > > > And, I think we should have the check of SND_PCM_STATE_SUSPENDED at > > the beginning of snd_pcm_dmix_drain() before entering to the loop, > > too. > > > > Last but not least, the very same bug is present for dshare. Could > > you fix this together? > > > Ok, I will refine the patch. But one thing I don't understand is that why need > to check the SND_PCM_STATE_SUSPENDED before entering the loop, seems check the > state in the loop can resolve the issue. It's just a minor optimization. The check isn't done at the beginning of the loop but after a few other calls (sync_ptr and sync_area) to be skipped at PM. Takashi