From: Jiada Wang <jiada_wang@mentor.com>
To: Clemens Ladisch <clemens@ladisch.de>
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: [PATCH 1/3 v1] ALSA: usb-audio: more tolerant packetsize
Date: Thu, 1 Dec 2016 03:36:26 -0800 [thread overview]
Message-ID: <58400B3A.7080806@mentor.com> (raw)
In-Reply-To: <1cb0aa49-62d5-b2ac-a473-bbce3f491d59@ladisch.de>
Hello Clemens
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
>
>> have a much higher jitter in used packetsizes than 25%
> How high? (Please note that the USB specification restricts the jitter
> to at most one frame in consecutive packets.)
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)
which caused the babble and dropping of that packets.
Thanks,
Jiada
>> which would result in BABBLE condition and dropping of packets.
>> A better solution is so assume the jitter to be the nominal packetsize
> This solution is better for this one particular device, but how does it
> affect normal devices, or the Scarlett 2i4 on EHCI affected?
>
>
> Regards,
> Clemens
next prev parent reply other threads:[~2016-12-01 11:36 UTC|newest]
Thread overview: 35+ 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 ` Jiada Wang
2016-11-30 7:59 ` [PATCH 1/3 v1] ALSA: usb-audio: more tolerant packetsize Jiada Wang
2016-11-30 7:59 ` Jiada Wang
2016-11-30 8:54 ` Takashi Iwai
2016-11-30 8:54 ` Takashi Iwai
2016-12-01 7:04 ` Jiada Wang
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
2016-12-01 11:36 ` Jiada Wang [this message]
2016-12-01 12:15 ` Clemens Ladisch
2016-12-02 5:53 ` Jiada Wang
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 7:59 ` Jiada Wang
2016-11-30 8:51 ` Takashi Iwai
2016-11-30 8:51 ` Takashi Iwai
2016-12-01 7:07 ` Jiada Wang
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 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 7:59 ` Jiada Wang
2016-11-30 9:00 ` Takashi Iwai
2016-11-30 9:00 ` Takashi Iwai
2016-12-05 10:10 ` Jiada Wang
2016-12-05 10:10 ` Jiada Wang
2016-12-05 10:30 ` Takashi Iwai
2016-12-05 10:30 ` Takashi Iwai
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