From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: "Liao, Bard" <bard.liao@intel.com>, Vinod Koul <vkoul@kernel.org>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
"tiwai@suse.de" <tiwai@suse.de>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"broonie@kernel.org" <broonie@kernel.org>,
"srinivas.kandagatla@linaro.org" <srinivas.kandagatla@linaro.org>,
"Kale, Sanyog R" <sanyog.r.kale@intel.com>,
Bard Liao <yung-chuan.liao@linux.intel.com>
Subject: Re: [PATCH 7/7] soundwire: intel: remove PDM support
Date: Mon, 10 Jan 2022 10:32:32 -0600 [thread overview]
Message-ID: <0cb18de1-dcff-e3c8-414e-b5b96b30b387@linux.intel.com> (raw)
In-Reply-To: <DM6PR11MB407458F1824D52BFD0D9ED96FF7E9@DM6PR11MB4074.namprd11.prod.outlook.com>
>>>>> While the hardware supports PDM streams, this capability has never
>>>>> been tested or enabled on any product, so this is dead-code. Let's
>>>>> remove all this.
>>>>
>>>> So no plans to test and enable this? Do the DMICs not use PDM?
>>>
>>> The point is that this code is unused/untested. We can re-add it after
>>> it was tested.
>>
>> That does not answer my question. Do the DMICs not use PDM?
>
> I will leave the question to Pierre. 😊
traditional digital microphones using the Nokia spec with two
microphones using opposite clock edges do use PDM.
PDM over SoundWire is possible as well, it's e.g. used by Qualcomm for
amplifiers. This patch does not make a statement on whether PDM support
makes sense or not in general.
As mentioned above on Intel platforms the hardware is in theory capable
of supporting PDM, but that capability has never been deployed, all
existing devices we connect to are PCM based and all the PDM references
are essentially untested - and likely broken.
next prev parent reply other threads:[~2022-01-10 16:49 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 5:46 [PATCH 0/7] ASoC/SoundWire: improve suspend flows and use set_stream() instead of set_tdm_slots() for HDAudio Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-13 5:46 ` [PATCH 1/7] ASOC: SOF: Intel: use snd_soc_dai_get_widget() Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-13 5:46 ` [PATCH 2/7] ASoC/soundwire: intel: simplify callbacks for params/hw_free Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-23 16:30 ` Vinod Koul
2021-12-23 16:30 ` Vinod Koul
2021-12-13 5:46 ` [PATCH 3/7] soundwire: intel: improve suspend flows Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-23 6:56 ` Vinod Koul
2021-12-23 6:56 ` Vinod Koul
2021-12-13 5:46 ` [PATCH 4/7] ASoC/SoundWire: dai: expand 'stream' concept beyond SoundWire Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-23 16:35 ` Vinod Koul
2021-12-23 16:35 ` Vinod Koul
2021-12-13 5:46 ` [PATCH 5/7] ASoC: Intel/SOF: use set_stream() instead of set_tdm_slots() for HDAudio Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-13 5:46 ` [PATCH 6/7] soundwire: intel: remove unnecessary init Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-23 6:58 ` Vinod Koul
2021-12-23 6:58 ` Vinod Koul
2021-12-13 5:46 ` [PATCH 7/7] soundwire: intel: remove PDM support Bard Liao
2021-12-13 5:46 ` Bard Liao
2021-12-23 6:59 ` Vinod Koul
2021-12-23 6:59 ` Vinod Koul
2021-12-23 7:46 ` Liao, Bard
2021-12-23 7:46 ` Liao, Bard
2021-12-23 11:05 ` Vinod Koul
2021-12-23 11:05 ` Vinod Koul
2021-12-23 12:29 ` Liao, Bard
2021-12-23 12:29 ` Liao, Bard
2022-01-10 16:32 ` Pierre-Louis Bossart [this message]
2021-12-23 16:35 ` Vinod Koul
2021-12-23 16:35 ` Vinod Koul
2021-12-23 18:26 ` Mark Brown
2021-12-23 18:26 ` Mark Brown
2021-12-24 1:38 ` Liao, Bard
2021-12-24 1:38 ` Liao, Bard
2021-12-21 18:09 ` [PATCH 0/7] ASoC/SoundWire: improve suspend flows and use set_stream() instead of set_tdm_slots() for HDAudio Mark Brown
2021-12-21 18:09 ` Mark Brown
2021-12-22 13:47 ` Liao, Bard
2021-12-22 13:47 ` Liao, Bard
2021-12-23 5:19 ` Vinod Koul
2021-12-23 5:19 ` Vinod Koul
2021-12-24 16:17 ` Mark Brown
2021-12-24 16:17 ` Mark Brown
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