From: Clemens Ladisch <clemens@ladisch.de>
To: Jiada Wang <jiada_wang@mentor.com>
Cc: alsa-devel@alsa-project.org, tiwai@suse.com,
linux-kernel@vger.kernel.org, Mark_Craske@mentor.com,
apape@de.adit-jv.com
Subject: Re: [alsa-devel] [PATCH 1/3 v1] ALSA: usb-audio: more tolerant packetsize
Date: Thu, 1 Dec 2016 13:15:39 +0100 [thread overview]
Message-ID: <b869176e-54e4-a47c-98ab-11be08ca0e61@ladisch.de> (raw)
In-Reply-To: <58400B3A.7080806@mentor.com>
Jiada Wang wrote:
> On 11/30/2016 11:41 PM, Clemens Ladisch wrote:
>> Jiada Wang wrote:
>>> since commit 57e6dae1087bbaa6b33d3dd8a8e90b63888939a3 the expected packetsize is always limited to
>>> nominal + 25%. It was discovered, that some devices
>>
>> Which devices?
>
> It was a LG nexus
So it was the Android audio accessory mode.
>>> have a much higher jitter in used packetsizes than 25%
>>
>> How high?
>
> the nominal packet size was somewhere around 176bytes
> +25% would result in max expected packets to be ~220bytes
> We observed some packets exceeding this size (256byte)
256 bytes per USB frame would correspond to 64 kHz, instead of the
nominal 44.1 kHz.
The audio accessory sample format is fixed, and that mode is no longer
developed, so increasing the limit to +50% would be sufficient to work
around this problem.
I don't know if this is a bug in Google's generic AOA code, or if LG did
some changes; I have not heard any other report so far ...
Regards,
Clemens
next prev parent reply other threads:[~2016-12-01 12:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 7:59 [PATCH 0/3 v1] usb-misc fix Jiada Wang
2016-11-30 7:59 ` [PATCH 1/3 v1] ALSA: usb-audio: more tolerant packetsize Jiada Wang
2016-11-30 8:54 ` Takashi Iwai
2016-12-01 7:04 ` Jiada Wang
2016-12-01 7:41 ` [alsa-devel] " Clemens Ladisch
2016-12-01 8:58 ` Takashi Iwai
2016-12-01 11:16 ` Clemens Ladisch
2016-12-01 11:23 ` Takashi Iwai
2016-12-01 11:50 ` Clemens Ladisch
[not found] ` <58400B3A.7080806@mentor.com>
2016-12-01 12:15 ` Clemens Ladisch [this message]
2016-11-30 7:59 ` [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus Jiada Wang
2016-11-30 8:51 ` Takashi Iwai
2016-12-01 7:07 ` Jiada Wang
2016-11-30 10:45 ` Takashi Sakamoto
2016-11-30 22:19 ` Takashi Sakamoto
2016-12-05 7:32 ` Jiada Wang
2016-12-05 9:58 ` Takashi Sakamoto
2016-11-30 7:59 ` [PATCH 3/3 v3] ALSA: usb-audio: fix race in snd_usb_endpoint_stop Jiada Wang
2016-11-30 9:00 ` Takashi Iwai
2016-12-05 10:10 ` Jiada Wang
2016-12-05 10:30 ` Takashi Iwai
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