From: Jerome Brunet <jbrunet@baylibre.com>
To: Mark Brown <broonie@kernel.org>, Liam Girdwood <lgirdwood@gmail.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>,
alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
Kevin Hilman <khilman@baylibre.com>
Subject: [PATCH RFC] ASoC: dai playback_active and capture_active may be greater than 1
Date: Thu, 19 Apr 2018 16:06:12 +0200 [thread overview]
Message-ID: <20180419140612.11049-1-jbrunet@baylibre.com> (raw)
At the moment playback_active and capture_active are using only 1 bit so
the maximum active count is 1.
However, snd_soc_runtime_activate() may be called several time on the
same dai. This happens when a dai is part of several dai_links. It is
often the case for "snd-soc-dummy-dai".
This is a problem if snd_soc_runtime_activate() is called an even number
of times on a dai. In this case the active count overflow back to 0. As
consequence, ASoC functions, such as soc_dpcm_runtime_update(), won't run
correctly.
Storing these usage counts on plain 'unsigned int' solves the problem.
Fixes: f0fba2ad1b6b ("ASoC: multi-component - ASoC Multi-Component Support")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
Hi,
I found this problem while working on ASoC support for a new platform.
During a playback, using DPCM, if I changed the backend dai, nothing
happened, old backend path was not pruned, new backend path was not added.
Here is how it goes:
1 FE and 2 BE, all 3 using snd-soc-dummy-dai for the codec_dai (ATM).
On playback start:
- BE #1 activates and increments snd-soc-dummy-dai's playback_active
- FE activates and increments snd-soc-dummy-dai's playback_active
The playback works but snd-soc-dummy-dai's playback_active value is now 0.
Through a mux kcontrol, change BE client of FE, from BE #1 to BE #2.
-> trigger soc_dpcm_runtime_update().
-> checks fe's codec_dai playback_active which is zero so playback
path processing is skipped, keeping the old invalid path.
include/sound/soc-dai.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
index 8ad11669e4d8..35ebb0be5114 100644
--- a/include/sound/soc-dai.h
+++ b/include/sound/soc-dai.h
@@ -294,8 +294,8 @@ struct snd_soc_dai {
struct snd_soc_dai_driver *driver;
/* DAI runtime info */
- unsigned int capture_active:1; /* stream is in use */
- unsigned int playback_active:1; /* stream is in use */
+ unsigned int capture_active; /* stream usage count */
+ unsigned int playback_active; /* stream usage count */
unsigned int probed:1;
unsigned int active;
--
2.14.3
next reply other threads:[~2018-04-19 14:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-19 14:06 Jerome Brunet [this message]
2018-04-30 15:10 ` [alsa-devel] [PATCH RFC] ASoC: dai playback_active and capture_active may be greater than 1 Charles Keepax
2018-05-01 21:07 ` Applied "ASoC: dai playback and capture active may be greater than 1" to the asoc tree Mark Brown
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