From 3e5b50165fd0be080044586f43fcdd460ed27610 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 28 Apr 2009 12:07:08 +0200 Subject: [PATCH] ALSA: pcm core - Avoid jiffies check for devices with BATCH flag The hardware devices with SNDRV_PCM_INFO_BATCH flag can't give the precise current position. And such hardwares have often big FIFO in addition to the ring buffer, and it screws up the jiffies check in pcm_lib.c. This patch adds a simple check of info flag so that the driver skips the jiffies check in snd_pcm_period_elapsed() when BATCH flag is set. Signed-off-by: Takashi Iwai --- sound/core/pcm_lib.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 63d088f2265..a2a792c18c4 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -249,6 +249,12 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream) new_hw_ptr = hw_base + pos; } } + /* Skip the jiffies check for hardwares with BATCH flag. + * Such hardware usually just increases the position at each IRQ, + * thus it can't give any strange position. + */ + if (runtime->hw.info & SNDRV_PCM_INFO_BATCH) + goto no_jiffies_check; hdelta = new_hw_ptr - old_hw_ptr; jdelta = jiffies - runtime->hw_ptr_jiffies; if (((hdelta * HZ) / runtime->rate) > jdelta + HZ/100) { @@ -272,6 +278,7 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream) hw_base -= hw_base % runtime->buffer_size; delta = 0; } + no_jiffies_check: if (delta > runtime->period_size + runtime->period_size / 2) { hw_ptr_error(substream, "Lost interrupts? " -- 2.39.5