Re: DWC3-Gadget: Flickering with ISOC Streaming (UVC) while multiplier set on Superspeed

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Wed, Sep 06, 2023, Thinh Nguyen wrote:
> 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.

Clarification: no mult setting for the dwc3 controller when operate in
SuperSpeed.

Thinh

> 
> 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