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From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: "Ughreja, Rakesh A" <rakesh.a.ughreja@intel.com>,
	"Kp, Jeeja" <jeeja.kp@intel.com>,
	"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>
Cc: "R, Dharageswari" <dharageswari.r@intel.com>,
	"tiwai@suse.de" <tiwai@suse.de>,
	"Shah, Hardik T" <hardik.t.shah@intel.com>,
	Patches Audio <patches.audio@intel.com>,
	"broonie@kernel.org" <broonie@kernel.org>,
	"Girdwood, Liam R" <liam.r.girdwood@intel.com>
Subject: Re: [PATCH 09/11] ASoC: Intel: Skylake: Fix DMA position reporting for capture stream
Date: Thu, 23 Mar 2017 10:31:30 -0500	[thread overview]
Message-ID: <b73996bd-1a67-1f6a-e6da-04dd9c719451@linux.intel.com> (raw)
In-Reply-To: <85DFEED57DC57344B2483EF7BF8CB60552D0BABB@BGSMSX104.gar.corp.intel.com>


>>>  	 * HAD space reflects the actual data that is transferred.
>>>  	 * Use the position buffer for capture, as DPIB write gets
>>>  	 * completed earlier than the actual data written to the DDR.
>>> +	 *
>>> +	 * For capture stream following workaround is required to fix the
>>> +	 * incorrect position reporting.
>>> +	 *
>>> +	 * 1. Wait for 20us before reading the DMA position in buffer once
>>> +	 * the interrupt is generated for stream completion.
>>
>> is this really 20us regardless of the sampling frequency/channel count?
>> 20us is one sample at 48kHz so wondering how generic this work-around is...
>
> Yes, this is independent of PCM parameters. Update happens on the
> HDA frame boundary i.e. 20.833uSec.

Makes sense. it's worth updating the comments though to make it 
self-explanatory.

  reply	other threads:[~2017-03-23 15:31 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-23 13:31 [PATCH 00/11] ASoC: Intel: Skylake: More driver updates jeeja.kp
2017-03-23 13:31 ` [PATCH 01/11] ALSA: hda: Fix LLCH register read jeeja.kp
2017-03-29 11:02   ` Applied "ALSA: hda: Fix LLCH register read" to the asoc tree Mark Brown
2017-03-23 13:31 ` [PATCH 02/11] ASoC: Intel: Skylake: Use the sig_bits to define dai bps capability jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Use the sig_bits to define dai bps capability" to the asoc tree Mark Brown
2017-03-23 13:31 ` [PATCH 03/11] ASoC: hdac_hdmi: Update sig_bits based on converter capability jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: hdac_hdmi: Update sig_bits based on converter capability" to the asoc tree Mark Brown
2017-03-23 13:31 ` [PATCH 04/11] ASoC: Intel: Skylake: Add 16-bit constraint to FE bxt_rt298 machine jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Add 16-bit constraint to FE bxt_rt298 machine" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 05/11] ASoC: Intel: Skylake: Don't unload module when in use jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Don't unload module when in use" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 06/11] ASoC: Intel: Skylake: Remove redundant vmixer handler jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Remove redundant vmixer handler" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 07/11] ASoC: Intel: Skylake: remove hard coded ACPI path jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: remove hard coded ACPI path" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 08/11] ASoC: Intel: Skylake: Rearrangement of code to cleanup SKL SST library jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Rearrangement of code to cleanup SKL SST library" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 09/11] ASoC: Intel: Skylake: Fix DMA position reporting for capture stream jeeja.kp
2017-03-23 14:12   ` Pierre-Louis Bossart
2017-03-23 15:08     ` Ughreja, Rakesh A
2017-03-23 15:31       ` Pierre-Louis Bossart [this message]
2017-03-23 13:32 ` [PATCH 10/11] ASoC: Intel: Skylake: Fix module state after unbind and delete jeeja.kp
2017-03-29 11:54   ` Applied "ASoC: Intel: Skylake: Fix module state after unbind and delete" to the asoc tree Mark Brown
2017-03-23 13:32 ` [PATCH 11/11] ASoC: Intel: Skylake: Add support for deferred DSP module bind jeeja.kp
2017-04-12 16:00   ` Applied "ASoC: Intel: Skylake: Add support for deferred DSP module bind" to the asoc tree Mark Brown
2017-03-27  3:22 ` [PATCH 00/11] ASoC: Intel: Skylake: More driver updates Vinod Koul

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