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From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
To: tiwai@suse.de
Cc: alsa-devel@alsa-project.org
Subject: [PATCH alsa-lib 05/12] pcm: hw: use helper function to query status/control data after PREPARE/RESET call
Date: Fri, 30 Jun 2017 08:58:21 +0900	[thread overview]
Message-ID: <20170629235828.18076-6-o-takashi@sakamocchi.jp> (raw)
In-Reply-To: <20170629235828.18076-1-o-takashi@sakamocchi.jp>

In ALSA PCM core, calls of ioctl(2) with SNDRV_PCM_IOCTL_PREPARE and
SNDRV_PCM_IOCTL_RESET have effects to initialize appl_ptr to current
hw_ptr and shift state of runtime. On the other hand, avail_min of the
runtime is kept as is.

In a fallback mode of status data mapping, after executing the call,
applications should execute ioctl(2) with SNDRV_PCM_IOCTL_SYNC_PTR to
query appl_ptr and the state, while don't need to issue avail_min.

This commit applies a minor optimization to the call.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 src/pcm/pcm_hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index aa548529..6f20cbff 100644
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -615,7 +615,7 @@ static int snd_pcm_hw_prepare(snd_pcm_t *pcm)
 		SYSMSG("SNDRV_PCM_IOCTL_PREPARE failed (%i)", err);
 		return err;
 	}
-	return sync_ptr(hw, SNDRV_PCM_SYNC_PTR_APPL);
+	return query_state(hw);
 }
 
 static int snd_pcm_hw_reset(snd_pcm_t *pcm)
@@ -627,7 +627,7 @@ static int snd_pcm_hw_reset(snd_pcm_t *pcm)
 		SYSMSG("SNDRV_PCM_IOCTL_RESET failed (%i)", err);
 		return err;
 	}
-	return sync_ptr(hw, SNDRV_PCM_SYNC_PTR_APPL);
+	return query_state(hw);
 }
 
 static int snd_pcm_hw_start(snd_pcm_t *pcm)
-- 
2.11.0

  parent reply	other threads:[~2017-06-29 23:58 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-29 23:58 [PATCH alsa-lib 00/12] pcm: hw: optimization for v2.0.14 of PCM protocol/interface Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 01/12] pcm: hw: fix to initialize function local variable Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 02/12] pcm: hw: add a helper function just to query status/control data of PCM substream Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 03/12] pcm: hw: use heler function to query status/control data after reading/writing PCM frames Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 04/12] pcm: hw: use helper function to query status/control data after HW_PARAMS call Takashi Sakamoto
2017-06-29 23:58 ` Takashi Sakamoto [this message]
2017-06-29 23:58 ` [PATCH alsa-lib 06/12] pcm: hw: use helper function to query status/control data after REWIND/FORWARD call Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 07/12] pcm: hw: use helper function to query status/control data for calculation of available space on PCM buffer Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 08/12] pcm: hw: add a helper function to request hwsync without side-effects Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 09/12] pcm: hw: add a helper function to issue appl_ptr without sub-effects Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 10/12] pcm: hw: add a helper function to issue avail_min " Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 11/12] pcm: hw: remove superfluous code to call of SNDRV_PCM_IOCTL_SYNC_PTR in snd_pcm_hw_forward() Takashi Sakamoto
2017-06-29 23:58 ` [PATCH alsa-lib 12/12] pcm: hw: minor refactoring for initialization of control data Takashi Sakamoto
2017-06-30  6:43 ` [PATCH alsa-lib 00/12] pcm: hw: optimization for v2.0.14 of PCM protocol/interface Takashi Sakamoto

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