From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pz0-f191.google.com (mail-pz0-f191.google.com [209.85.222.191]) by ozlabs.org (Postfix) with ESMTP id 7448A100835 for ; Sat, 7 Nov 2009 19:34:08 +1100 (EST) Received: by mail-pz0-f191.google.com with SMTP id 29so1161651pzk.17 for ; Sat, 07 Nov 2009 00:34:08 -0800 (PST) Sender: Grant Likely From: Grant Likely Subject: [PATCH 2/6] ASoC/mpc5200: get rid of the appl_ptr tracking nonsense To: linuxppc-dev@lists.ozlabs.org, alsa-devel@alsa-project.org, broonie@opensource.wolfsonmicro.com Date: Sat, 07 Nov 2009 01:34:05 -0700 Message-ID: <20091107083358.18908.10635.stgit@angua> In-Reply-To: <20091107081631.18908.82921.stgit@angua> References: <20091107081631.18908.82921.stgit@angua> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: lrg@slimlogic.co.uk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sound drivers PCM DMA is supposed to free-run until told to stop by the trigger callback. The current code tries to track appl_ptr, to avoid stale buffer data getting played out at the end of the data stream. Unfortunately it also results in race conditions which can cause the audio to stall. Signed-off-by: Grant Likely --- sound/soc/fsl/mpc5200_dma.c | 52 +++++++------------------------------------ sound/soc/fsl/mpc5200_dma.h | 2 -- 2 files changed, 8 insertions(+), 46 deletions(-) diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c index 986d3c8..4e47586 100644 --- a/sound/soc/fsl/mpc5200_dma.c +++ b/sound/soc/fsl/mpc5200_dma.c @@ -65,36 +65,6 @@ static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s) s->period_next = (s->period_next + 1) % s->runtime->periods; } -static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s) -{ - if (s->appl_ptr > s->runtime->control->appl_ptr) { - /* - * In this case s->runtime->control->appl_ptr has wrapped around. - * Play the data to the end of the boundary, then wrap our own - * appl_ptr back around. - */ - while (s->appl_ptr < s->runtime->boundary) { - if (bcom_queue_full(s->bcom_task)) - return; - - s->appl_ptr += s->runtime->period_size; - - psc_dma_bcom_enqueue_next_buffer(s); - } - s->appl_ptr -= s->runtime->boundary; - } - - while (s->appl_ptr < s->runtime->control->appl_ptr) { - - if (bcom_queue_full(s->bcom_task)) - return; - - s->appl_ptr += s->runtime->period_size; - - psc_dma_bcom_enqueue_next_buffer(s); - } -} - /* Bestcomm DMA irq handler */ static irqreturn_t psc_dma_bcom_irq_tx(int irq, void *_psc_dma_stream) { @@ -107,8 +77,9 @@ static irqreturn_t psc_dma_bcom_irq_tx(int irq, void *_psc_dma_stream) bcom_retrieve_buffer(s->bcom_task, NULL, NULL); s->period_current = (s->period_current+1) % s->runtime->periods; + + psc_dma_bcom_enqueue_next_buffer(s); } - psc_dma_bcom_enqueue_tx(s); spin_unlock(&s->psc_dma->lock); /* If the stream is active, then also inform the PCM middle layer @@ -182,28 +153,21 @@ static int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd) s->period_next = 0; s->period_current = 0; s->active = 1; - - /* track appl_ptr so that we have a better chance of detecting - * end of stream and not over running it. - */ s->runtime = runtime; - s->appl_ptr = s->runtime->control->appl_ptr - - (runtime->period_size * runtime->periods); /* Fill up the bestcomm bd queue and enable DMA. * This will begin filling the PSC's fifo. */ spin_lock_irqsave(&psc_dma->lock, flags); - if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) { + if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) bcom_gen_bd_rx_reset(s->bcom_task); - for (i = 0; i < runtime->periods; i++) - if (!bcom_queue_full(s->bcom_task)) - psc_dma_bcom_enqueue_next_buffer(s); - } else { + else bcom_gen_bd_tx_reset(s->bcom_task); - psc_dma_bcom_enqueue_tx(s); - } + + for (i = 0; i < runtime->periods; i++) + if (!bcom_queue_full(s->bcom_task)) + psc_dma_bcom_enqueue_next_buffer(s); bcom_enable(s->bcom_task); spin_unlock_irqrestore(&psc_dma->lock, flags); diff --git a/sound/soc/fsl/mpc5200_dma.h b/sound/soc/fsl/mpc5200_dma.h index 529f7a0..d9c741b 100644 --- a/sound/soc/fsl/mpc5200_dma.h +++ b/sound/soc/fsl/mpc5200_dma.h @@ -19,8 +19,6 @@ */ struct psc_dma_stream { struct snd_pcm_runtime *runtime; - snd_pcm_uframes_t appl_ptr; - int active; struct psc_dma *psc_dma; struct bcom_task *bcom_task;