From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: Takashi Iwai <tiwai@suse.de>
Cc: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>,
"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
Kai Vehmanen <kai.vehmanen@linux.intel.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
"Rojewski, Cezary" <cezary.rojewski@intel.com>,
Takashi Iwai <tiwai@suse.com>,
Jie Yang <yang.jie@linux.intel.com>,
Yu-Hsuan Hsu <yuhsuan@chromium.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Liam Girdwood <liam.r.girdwood@linux.intel.com>,
Sam McNally <sammc@chromium.org>, Mark Brown <broonie@kernel.org>,
"yuhsuan@google.com" <yuhsuan@google.com>,
Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
Daniel Stuart <daniel.stuart14@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Lu, Brent" <brent.lu@intel.com>,
Damian van Soelen <dj.vsoelen@gmail.com>
Subject: Re: [PATCH v3 2/2] ASoC: Intel: Add period size constraint on strago board
Date: Wed, 12 Aug 2020 10:54:30 -0500 [thread overview]
Message-ID: <be45d821-57c6-6ca5-0864-ac3aa521d82e@linux.intel.com> (raw)
In-Reply-To: <s5hv9hnx6am.wl-tiwai@suse.de>
On 8/12/20 9:55 AM, Takashi Iwai wrote:
> On Wed, 12 Aug 2020 16:46:40 +0200,
> Pierre-Louis Bossart wrote:
>>
>>
>>>>>>>> After doing some experiments, I think I can identify the problem more precisely.
>>>>>>>> 1. aplay can not reproduce this issue because it writes samples
>>>>>>>> immediately when there are some space in the buffer. However, you can
>>>>>>>> add --test-position to see how the delay grows with period size 256.
>>>>>>>>> aplay -Dhw:1,0 --period-size=256 --buffer-size=480 /dev/zero -d 1 -f dat --test-position
>>>>>>>> Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000
>>>>>>>> Hz, Stereo
>>>>>>>> Suspicious buffer position (1 total): avail = 0, delay = 2064, buffer = 512
>>>>>>>> Suspicious buffer position (2 total): avail = 0, delay = 2064, buffer = 512
>>>>>>>> Suspicious buffer position (3 total): avail = 0, delay = 2096, buffer = 512
>>>>>>>> ...
>>>>>>>
>>>>>>> Isn't this about the alignment of the buffer size against the period
>>>>>>> size, not the period size itself? i.e. in the example above, the
>>>>>>> buffer size isn't a multiple of period size, and DSP can't handle if
>>>>>>> the position overlaps the buffer size in a half way.
>>>>>>>
>>>>>>> If that's the problem (and it's an oft-seen restriction), the right
>>>>>>> constraint is
>>>>>>> snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
>>>>>>>
>>>>>>>
>>>>>>> Takashi
>>>>>> Oh sorry for my typo. The issue happens no matter what buffer size is
>>>>>> set. Actually, even if I want to set 480, it will change to 512
>>>>>> automatically.
>>>>>> Suspicious buffer position (1 total): avail = 0, delay = 2064, buffer
>>>>>> = 512 <-this one is the buffer size
>>>>>
>>>>> OK, then it means that the buffer size alignment is already in place.
>>>>>
>>>>> And this large delay won't happen if you use period size 240?
>>>>>
>>>>>
>>>>> Takashi
>>>> Yes! If I set the period size to 240, it will not print "Suspicious
>>>> buffer position ..."
>>>
>>> So it sounds like DSP handles the delay report incorrectly.
>>> Then it comes to another question: the driver supports both SOF and
>>> SST. Is there the behavior difference between both DSPs wrt this
>>> delay issue?
>>
>> I still don't get what the issue is. The two following cases work fine
>> with the SST/Atom driver:
>>
>> root@chrx:~# aplay -Dhw:0,0 --period-size=240 --buffer-size=480
>> /dev/zero -d 2 -f dat --test-position
>> Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000
>> Hz, Stereo
>> root@chrx:~# aplay -Dhw:0,0 --period-size=960 --buffer-size=4800
>> /dev/zero -d 2 -f dat --test-position
>> Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000
>> Hz, Stereo
>
> What if with --period-size=256 --buffer-size=512 and --test-position?
> Can you reproduce the problem in your side?
Yes indeed with the existing driver:
root@chrx:~# aplay -Dhw:0,0 --period-size=256 --buffer-size=512
/dev/zero -d 2 -f dat --test-position
Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000
Hz, Stereo
underrun!!! (at least 0.312 ms long)
underrun!!! (at least 0.326 ms long)
Suspicious buffer position (1 total): avail = 0, delay = 2064, buffer = 512
Suspicious buffer position (2 total): avail = 0, delay = 2064, buffer = 512
Suspicious buffer position (3 total): avail = 0, delay = 2080, buffer = 512
Suspicious buffer position (4 total): avail = 0, delay = 2080, buffer = 512
Suspicious buffer position (5 total): avail = 0, delay = 2096, buffer = 512
Suspicious buffer position (6 total): avail = 0, delay = 2096, buffer = 512
but the new constraint to force a 1ms step added in the patch1 should
preclude this from happening.
>> The existing code has this:
>>
>> /* Make sure, that the period size is always even */
>> snd_pcm_hw_constraint_step(substream->runtime, 0,
>> SNDRV_PCM_HW_PARAM_PERIODS, 2);
>>
>> return snd_pcm_hw_constraint_integer(runtime,
>> SNDRV_PCM_HW_PARAM_PERIODS);
>>
>> and with the addition of period size being a multiple of 1ms all
>> requirements should be met?
>
> I also wonder what's really missing, too :)
>
> BTW, I took a look back at the thread, and CRAS seems using a very
> large buffer, namely:
> [ 52.434791] sound pcmC1D0p: PERIOD_SIZE [240:240]
> [ 52.434802] sound pcmC1D0p: BUFFER_SIZE [204480:204480]
yes, that's 852 periods and 4.260 seconds. Never seen such values :-)
next prev parent reply other threads:[~2020-08-12 15:55 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 11:03 [PATCH 0/2] Add period size constraint for Atom Chromebook Brent Lu
2020-07-29 11:03 ` [PATCH 1/2] ASoC: intel: atom: Add period size constraint Brent Lu
2020-07-29 11:19 ` Andy Shevchenko
2020-07-29 11:03 ` [PATCH 2/2] ASoC: Intel: Add period size constraint on strago board Brent Lu
2020-07-29 14:08 ` Pierre-Louis Bossart
2020-07-30 8:02 ` Lu, Brent
2020-07-30 15:27 ` Pierre-Louis Bossart
2020-07-30 15:44 ` Pierre-Louis Bossart
2020-07-30 16:17 ` Lu, Brent
2020-07-30 16:56 ` Takashi Iwai
2020-07-31 12:28 ` Lu, Brent
2020-07-29 11:20 ` [PATCH 0/2] Add period size constraint for Atom Chromebook Andy Shevchenko
2020-07-31 12:26 ` [PATCH v3 " Brent Lu
2020-07-31 12:26 ` [PATCH v3 1/2] ASoC: intel: atom: Add period size constraint Brent Lu
2020-07-31 12:26 ` [PATCH v3 2/2] ASoC: Intel: Add period size constraint on strago board Brent Lu
2020-07-31 13:34 ` Takashi Iwai
2020-08-01 8:58 ` Lu, Brent
2020-08-01 9:26 ` Takashi Iwai
2020-08-03 13:00 ` Lu, Brent
2020-08-03 15:13 ` Pierre-Louis Bossart
2020-08-03 16:45 ` Lu, Brent
2020-08-03 16:56 ` Takashi Iwai
2020-08-04 4:33 ` Lu, Brent
2020-08-04 14:24 ` Pierre-Louis Bossart
2020-08-06 16:41 ` Lu, Brent
2020-08-10 15:03 ` Pierre-Louis Bossart
2020-08-10 17:38 ` Yu-Hsuan Hsu
2020-08-11 2:16 ` Lu, Brent
2020-08-11 2:29 ` Yu-Hsuan Hsu
2020-08-11 7:43 ` Takashi Iwai
2020-08-11 8:25 ` Yu-Hsuan Hsu
2020-08-11 8:39 ` Takashi Iwai
2020-08-11 9:35 ` Yu-Hsuan Hsu
2020-08-11 14:53 ` Mark Brown
2020-08-11 16:54 ` Pierre-Louis Bossart
2020-08-11 17:22 ` Mark Brown
2020-08-12 3:09 ` Yu-Hsuan Hsu
2020-08-12 6:13 ` Takashi Iwai
2020-08-12 6:53 ` Yu-Hsuan Hsu
2020-08-12 6:58 ` Takashi Iwai
2020-08-12 7:43 ` Yu-Hsuan Hsu
2020-08-12 7:47 ` Takashi Iwai
2020-08-12 14:46 ` Pierre-Louis Bossart
2020-08-12 14:55 ` Takashi Iwai
2020-08-12 15:54 ` Pierre-Louis Bossart [this message]
2020-08-12 16:08 ` Lu, Brent
2020-08-12 16:38 ` Pierre-Louis Bossart
2020-08-13 6:24 ` Yu-Hsuan Hsu
2020-08-13 7:55 ` Lu, Brent
2020-08-13 8:36 ` Yu-Hsuan Hsu
2020-08-13 8:45 ` Takashi Iwai
2020-08-13 12:57 ` Pierre-Louis Bossart
2020-08-13 17:15 ` Yu-Hsuan Hsu
2020-08-21 16:40 ` [PATCH v3 0/2] Add period size constraint for Atom Chromebook Mark Brown
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