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From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Michael Grzeschik <mgr@pengutronix.de>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>
Subject: Re: DWC3-Gadget: Flickering with ISOC Streaming (UVC) while multiplier set on Superspeed
Date: Wed, 6 Sep 2023 23:05:21 +0000	[thread overview]
Message-ID: <20230906230510.vi7d4wnjeiapgtyk@synopsys.com> (raw)
In-Reply-To: <ZPgnwlOV1XP82kAY@pengutronix.de>

On Wed, Sep 06, 2023, Michael Grzeschik wrote:
> 
> > 2) Burst setting
> > 	I think this is self-explainatory. Large data request needs
> > 	higher burst.
> 
> I will have to find out if the burst setting can be changed on the
> rk3568 somehow. This sounds very likely.
> 

The dwc3 driver checks the endpoint descriptor from the UVC function
driver to setup the burst. So just setup the max 16 bursts (or 15 in the
descriptor). The dwc3 controller supports that. Whether the host would
do 16 bursts is another thing. Note that there's no "mult" setting for
SuperSpeed.

I recall that UVC tries to pack a lot of data in a single request. All
the while some intervals it would send 0-length data because of idle
time. I would spread to more requests with a little less data to give
the host a little more breathing room and bandwidth.

BR,
Thinh

  reply	other threads:[~2023-09-06 23:05 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-31 22:12 DWC3-Gadget: Flickering with ISOC Streaming (UVC) while multiplier set on Superspeed Michael Grzeschik
2023-09-01  1:35 ` Thinh Nguyen
2023-09-03 22:41   ` Michael Grzeschik
2023-09-04  0:42     ` Michael Grzeschik
2023-09-06  0:44       ` Thinh Nguyen
2023-09-06  6:40         ` Michael Grzeschik
2023-09-06  0:41     ` Thinh Nguyen
2023-09-06  7:18       ` Michael Grzeschik
2023-09-06 23:05         ` Thinh Nguyen [this message]
2023-09-06 23:09           ` Thinh Nguyen
2023-09-07 21:00             ` Michael Grzeschik
2023-09-07 23:33               ` Thinh Nguyen
2023-10-30 12:18                 ` Michael Grzeschik
2023-10-31 23:18                   ` Thinh Nguyen
2023-11-09 23:33                     ` [PATCH] usb: gadget: uvc: reduce the request size to increase the throughput Michael Grzeschik
2023-11-10  2:16                       ` Thinh Nguyen
2023-11-10 22:42                         ` Thinh Nguyen
2023-11-13  8:43                         ` Michael Grzeschik
2023-11-17  2:39                           ` Thinh Nguyen

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