From patchwork Tue Sep 5 16:18:21 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 9939279 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 19A2C60350 for ; Tue, 5 Sep 2017 16:18:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0A63B289AD for ; Tue, 5 Sep 2017 16:18:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F35C0289C6; Tue, 5 Sep 2017 16:18:32 +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 874D8289AD for ; Tue, 5 Sep 2017 16:18:31 +0000 (UTC) Received: from alsa0.perex.cz (localhost [127.0.0.1]) by alsa0.perex.cz (Postfix) with ESMTP id 00F152672B0; Tue, 5 Sep 2017 18:18:29 +0200 (CEST) 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 0F9BA2672B1; Tue, 5 Sep 2017 18:18:28 +0200 (CEST) Received: from Chamillionaire.breakpoint.cc (chamillionaire.breakpoint.cc [146.0.238.67]) by alsa0.perex.cz (Postfix) with ESMTP id E9BAD266C6D for ; Tue, 5 Sep 2017 18:18:23 +0200 (CEST) Received: from bigeasy by Chamillionaire.breakpoint.cc with local (Exim 4.84_2) (envelope-from ) id 1dpGVc-0005EZ-B9; Tue, 05 Sep 2017 18:15:28 +0200 Date: Tue, 5 Sep 2017 18:18:21 +0200 From: Sebastian Andrzej Siewior To: Takashi Sakamoto Message-ID: <20170905161820.jtysvxtfleunbbmf@breakpoint.cc> References: <20170901102537.8066-1-o-takashi@sakamocchi.jp> <19775981-a3f2-5f65-e934-bfe25db62a43@sakamocchi.jp> <20170905155351.2xmwyxrirndfwtgo@breakpoint.cc> <4cf46286-daf8-d52c-dacc-fa16052dcdb2@sakamocchi.jp> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4cf46286-daf8-d52c-dacc-fa16052dcdb2@sakamocchi.jp> User-Agent: NeoMutt/20170609 (1.8.3) Cc: alsa-devel@alsa-project.org, keescook@chromium.org, Takashi Iwai , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, john.stultz@linaro.org, tglx@linutronix.de, anna-maria@linutronix.de, hch@lst.de Subject: [alsa-devel] [PATCH 23/25 v3] ALSA/dummy: Replace tasklet with softirq hrtimer 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 From: Thomas Gleixner The tasklet is used to defer the execution of snd_pcm_period_elapsed() to the softirq context. Using the CLOCK_MONOTONIC_SOFT base invokes the timer callback in softirq context as well which renders the tasklet useless. Signed-off-by: Thomas Gleixner Signed-off-by: Anna-Maria Gleixner Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Takashi Sakamoto Cc: alsa-devel@alsa-project.org [o-takashi: avoid stall due to a call of hrtimer_cancel() on a callback of hrtimer] Signed-off-by: Takashi Sakamoto Signed-off-by: Sebastian Andrzej Siewior Tested-by: Takashi Sakamoto --- On 2017-09-06 01:05:43 [+0900], Takashi Sakamoto wrote: > As Iwai-san mentioned, in this function, .trigger can be called in two > cases; XRUN occurs and draining is done. Thus, let you change the comment as > 'In cases of XRUN and draining, this calls .trigger to stop PCM substream.'. > I'm sorry to trouble you. > > snd_pcm_period_elapsed() > ->snd_pcm_update_hw_ptr0() > ->snd_pcm_update_state() > ->snd_pcm_drain_done() > ... > ->.trigger(TRIGGER_STOP) > ->xrun() > ->snd_pcm_stop() > ... > ->.trigger(TRIGGER_STOP) > I think you asked me just to update the comment. Did I do it right? v2…v3: updated the comment as per Takashi Sakamoto's suggestion. v1…v2: merged Takashi Sakamoto fixup of the original patch into v2. sound/drivers/dummy.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c index dd5ed037adf2..cdd851286f92 100644 --- a/sound/drivers/dummy.c +++ b/sound/drivers/dummy.c @@ -376,17 +376,9 @@ struct dummy_hrtimer_pcm { ktime_t period_time; atomic_t running; struct hrtimer timer; - struct tasklet_struct tasklet; struct snd_pcm_substream *substream; }; -static void dummy_hrtimer_pcm_elapsed(unsigned long priv) -{ - struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv; - if (atomic_read(&dpcm->running)) - snd_pcm_period_elapsed(dpcm->substream); -} - static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer) { struct dummy_hrtimer_pcm *dpcm; @@ -394,7 +386,14 @@ static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer) dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer); if (!atomic_read(&dpcm->running)) return HRTIMER_NORESTART; - tasklet_schedule(&dpcm->tasklet); + /* + * In cases of XRUN and draining, this calls .trigger to stop PCM + * substream. + */ + snd_pcm_period_elapsed(dpcm->substream); + if (!atomic_read(&dpcm->running)) + return HRTIMER_NORESTART; + hrtimer_forward_now(timer, dpcm->period_time); return HRTIMER_RESTART; } @@ -414,14 +413,14 @@ static int dummy_hrtimer_stop(struct snd_pcm_substream *substream) struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data; atomic_set(&dpcm->running, 0); - hrtimer_cancel(&dpcm->timer); + if (!hrtimer_callback_running(&dpcm->timer)) + hrtimer_cancel(&dpcm->timer); return 0; } static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm) { hrtimer_cancel(&dpcm->timer); - tasklet_kill(&dpcm->tasklet); } static snd_pcm_uframes_t @@ -466,12 +465,10 @@ static int dummy_hrtimer_create(struct snd_pcm_substream *substream) if (!dpcm) return -ENOMEM; substream->runtime->private_data = dpcm; - hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC_SOFT, HRTIMER_MODE_REL); dpcm->timer.function = dummy_hrtimer_callback; dpcm->substream = substream; atomic_set(&dpcm->running, 0); - tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed, - (unsigned long)dpcm); return 0; }