Hi Pierre
We are working on a backport 3.14 branch for Chrome projects based on BDW platform. In the branch 4-channel capture is supported on some platforms but not all. So we need to add a constraint in the machine driver for machines don't support this feature.
I checked the for-next branch in the broonie repo. The channels_max of HSW_PCM_DAI_ID_SYSTEM is 4 for capture stream so I think it would have same issue like google's backport tree. I didn't find any constraint for this dai. Would you point out where it is?
.capture = { .stream_name = "Analog Capture", .channels_min = 2, .channels_max = 4, .rates = SNDRV_PCM_RATE_48000, .formats = SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S16_LE, },
Regards, Brent Lu
-----Original Message----- From: Pierre-Louis Bossart [mailto:pierre-louis.bossart@linux.intel.com] Sent: Friday, September 6, 2019 10:21 PM To: Lu, Brent brent.lu@intel.com; alsa-devel@alsa-project.org Cc: Rojewski, Cezary cezary.rojewski@intel.com; liam.r.girdwood@linux.intel.com; yang.jie@linux.intel.com; broonie@kernel.org; perex@perex.cz; tiwai@suse.com; kuninori.morimoto.gx@renesas.com; tglx@linutronix.de; linux-kernel@vger.kernel.org Subject: Re: [alsa-devel] [PATCH] ASoC: bdw-rt5677: channel constraint support
On 9/5/19 8:24 PM, Brent Lu wrote:
BDW boards using this machine driver supports only stereo capture and playback. Implement a constraint to enforce it.
Humm, can you clarify what problem/error this patch fixes?
There are already constraints on the hsw_dais[] where the channels are stereo only.
Thanks -Pierre
Signed-off-by: Brent Lu brent.lu@intel.com
sound/soc/intel/boards/bdw-rt5677.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)
diff --git a/sound/soc/intel/boards/bdw-rt5677.c b/sound/soc/intel/boards/bdw-rt5677.c index 4a4d335..a312b55 100644 --- a/sound/soc/intel/boards/bdw-rt5677.c +++ b/sound/soc/intel/boards/bdw-rt5677.c @@ -22,6 +22,8 @@
#include "../../codecs/rt5677.h"
+#define DUAL_CHANNEL 2
- struct bdw_rt5677_priv { struct gpio_desc *gpio_hp_en; struct snd_soc_component *component; @@ -245,6 +247,36 @@ static
int bdw_rt5677_init(struct snd_soc_pcm_runtime *rtd) return 0; }
+static const unsigned int channels[] = {
- DUAL_CHANNEL,
+};
+static const struct snd_pcm_hw_constraint_list constraints_channels = {
- .count = ARRAY_SIZE(channels),
- .list = channels,
- .mask = 0,
+};
+static int bdw_fe_startup(struct snd_pcm_substream *substream) {
- struct snd_pcm_runtime *runtime = substream->runtime;
- /*
* On this platform for PCM device we support,* stereo*/- runtime->hw.channels_max = DUAL_CHANNEL;
- snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
&constraints_channels);- return 0;
+}
+static const struct snd_soc_ops bdw_rt5677_fe_ops = {
- .startup = bdw_fe_startup,
+};
- /* broadwell digital audio interface glue - connects codec <--> CPU */ SND_SOC_DAILINK_DEF(dummy, DAILINK_COMP_ARRAY(COMP_DUMMY()));
@@ -273,6 +305,7 @@ static struct snd_soc_dai_link bdw_rt5677_dais[] = { }, .dpcm_capture = 1, .dpcm_playback = 1,
.ops = &bdw_rt5677_fe_ops,