From patchwork Fri Mar 23 09:03:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 10302947 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2882860384 for ; Fri, 23 Mar 2018 09:03:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1597D28C06 for ; Fri, 23 Mar 2018 09:03:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0783428D17; Fri, 23 Mar 2018 09:03:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D25D228C06 for ; Fri, 23 Mar 2018 09:03:52 +0000 (UTC) Received: from alsa0.perex.cz (localhost [127.0.0.1]) by alsa0.perex.cz (Postfix) with ESMTP id 5E39C2673E5; Fri, 23 Mar 2018 10:03:50 +0100 (CET) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa0.perex.cz (Postfix, from userid 1000) id 0A0BA2673F3; Fri, 23 Mar 2018 10:03:46 +0100 (CET) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id 7951D2673B2 for ; Fri, 23 Mar 2018 10:03:44 +0100 (CET) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 46BF1ADA5; Fri, 23 Mar 2018 09:03:43 +0000 (UTC) Date: Fri, 23 Mar 2018 10:03:42 +0100 Message-ID: From: Takashi Iwai To: "Wischer, Timo (ADITG/ESB)" In-Reply-To: References: <1521726537-7651-1-git-send-email-twischer@de.adit-jv.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Cc: "alsa-devel@alsa-project.org" Subject: Re: [alsa-devel] [PATCH - IOPLUG DRAIN 0/2] X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" 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 X-Virus-Scanned: ClamAV using ClamSMTP On Fri, 23 Mar 2018 09:08:43 +0100, Takashi Iwai wrote: > > On Fri, 23 Mar 2018 09:01:35 +0100, > Takashi Iwai wrote: > > > > On Fri, 23 Mar 2018 08:43:10 +0100, > > Wischer, Timo (ADITG/ESB) wrote: > > > > > > > No, again, in non-blocking mode, the drain callback will get never > > > > called. It's the responsibility of application to sync with poll() > > > > instead. > > > > > > Sorry but I do not get it anyway. > > > > > > The user application which is playing some audio has to do the following to drain in nonblocking mode, right? > > > snd_pcm_poll_descriptors(pfds) > > > while (snd_pcm_drain() == -EAGAIN) { > > > poll(pfds) > > > } > > > > > > > > > But in nonblocking mode the drain callback of the IO plugin will never be called with your solution. > > > Therefore in case of the pulse IO plugin which function should call pa_stream_drain()? > > > The user application will not do it directly and poll can also not call it. > > > > OK, now I understand your concern. Yes it's another missing piece, > > snd_pcm_ioplug_hw_ptr_update() needs to check the current state, and > > it drops to SETUP state instead of XRUN when it was DRAINING. > > Then application can simply do poll() and status update until it goes > > out of DRAINING state. > > > > But still it's outside the plugin, drain callback isn't called there. > > .... and now thinking of this again, the whole story can be folded > back: > > - The standard drain behavior can be implemented without plugin's own > code; it's just a poll and status check. > > - For any special case (or better implementation than poll()), we may > leave the whole draining callback action to each plugin; that's the > case of PA. Maybe it's easier to understand by a patch. Totally untested, but you get the idea from it. The check in snd_pcm_ioplug_hw_ptr_update() can be extended to the XRUN check, too. But do it in another patch. And, yeah, this still misses the proper non-blocking mode handling in pulse plugin. It's to be fixed there. Takashi -- 8< -- --- a/src/pcm/pcm_ioplug.c +++ b/src/pcm/pcm_ioplug.c @@ -47,6 +47,11 @@ typedef struct snd_pcm_ioplug_priv { snd_htimestamp_t trigger_tstamp; } ioplug_priv_t; +static int snd_pcm_ioplug_drop(snd_pcm_t *pcm); +static int snd_pcm_ioplug_poll_descriptors_count(snd_pcm_t *pcm); +static int snd_pcm_ioplug_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int space); +static int snd_pcm_ioplug_poll_revents(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int nfds, unsigned short *revents); + /* update the hw pointer */ /* called in lock */ static void snd_pcm_ioplug_hw_ptr_update(snd_pcm_t *pcm) @@ -57,6 +62,7 @@ static void snd_pcm_ioplug_hw_ptr_update(snd_pcm_t *pcm) hw = io->data->callback->pointer(io->data); if (hw >= 0) { snd_pcm_uframes_t delta; + snd_pcm_uframes_t avail; if ((snd_pcm_uframes_t)hw >= io->last_hw) delta = hw - io->last_hw; @@ -67,6 +73,12 @@ static void snd_pcm_ioplug_hw_ptr_update(snd_pcm_t *pcm) delta = wrap_point + hw - io->last_hw; } snd_pcm_mmap_hw_forward(io->data->pcm, delta); + /* stop the stream if all samples are drained */ + if (io->data->state == SND_PCM_STATE_DRAINING) { + avail = snd_pcm_mmap_avail(pcm); + if (avail >= pcm->buffer_size) + snd_pcm_ioplug_drop(pcm); + } io->last_hw = (snd_pcm_uframes_t)hw; } else io->data->state = SNDRV_PCM_STATE_XRUN; @@ -488,20 +500,66 @@ static int snd_pcm_ioplug_drop(snd_pcm_t *pcm) return 0; } +static int ioplug_drain_via_poll(snd_pcm_t *pcm) +{ + ioplug_priv_t *io = pcm->private_data; + int err; + + /* in non-blocking mode, leave application to poll() by itself */ + if (io->data->nonblock) + return -EAGAIN; + + while (io->data->state == SND_PCM_STATE_DRAINING) { + err = snd_pcm_wait_nocheck(pcm, -1); + snd_pcm_ioplug_hw_ptr_update(pcm); + if (err < 0) + break; + } + + return 0; +} + /* need own locking */ static int snd_pcm_ioplug_drain(snd_pcm_t *pcm) { ioplug_priv_t *io = pcm->private_data; int err; - if (io->data->state == SND_PCM_STATE_OPEN) + snd_pcm_lock(pcm); + switch (io->data->state) { + case SND_PCM_STATE_OPEN: + case SND_PCM_STATE_DISCONNECTED: + case SND_PCM_STATE_SUSPENDED: return -EBADFD; + case SND_PCM_STATE_PREPARED: + if (pcm->stream == SND_PCM_STREAM_PLAYBACK) { + err = snd_pcm_ioplug_start(pcm); + if (err < 0) + goto unlock; + io->data->state = SND_PCM_STATE_DRAINING; + } + break; + case SND_PCM_STATE_RUNNING: + io->data->state = SND_PCM_STATE_DRAINING; + break; + } - io->data->state = SND_PCM_STATE_DRAINING; - if (io->data->callback->drain) - io->data->callback->drain(io->data); - snd_pcm_lock(pcm); - err = snd_pcm_ioplug_drop(pcm); + if (io->data->state == SND_PCM_STATE_DRAINING) { + if (io->data->callback->drain) { + snd_pcm_unlock(pcm); /* let plugin own locking */ + err = io->data->callback->drain(io->data); + snd_pcm_lock(pcm); + } else { + err = ioplug_drain_via_poll(pcm); + } + if (err < 0) + goto unlock; + } + + if (io->data->state != SND_PCM_STATE_SETUP) + err = snd_pcm_ioplug_drop(pcm); + + unlock: snd_pcm_unlock(pcm); return err; }