RE: [RFC/PATCH 2/2 RESEND] usb:gadget: Add SuperSpeed support to the Gadget Framework

[Tanya Brokhman]

Resending since not everyone received my reply

-----Original Message-----
From: Brokhman Tatyana [mailto:tlinder@xxxxxxxxxxxxxx] 
Sent: Tuesday, October 12, 2010 11:18 AM
To: David Brownell
Cc: tlinder@xxxxxxxxxxxxxx; Sarah Sharp; linux-usb@xxxxxxxxxxxxxxx; Greg
Kroah-Hartman; Michal Nazarewicz; Randy Dunlap; Laurent Pinchart; Kyungmin
Park; Robert Lukassen; Matthew Wilcox; Fabien Chouteau; Tejun Heo;
linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [RFC/PATCH 2/2] usb:gadget: Add SuperSpeed support to the
Gadget Framework


>
>> > Ok.  I suppose whatever gadget application is being used can reset
>> these
>> > values later?  So that if you had a gadget webcam, it could set the
>> > wMaxPacketSize to the frame size or whatever it needed?
>
> Yes ... in fact, every altsetting or configuration may need to set up
> each endpoint differently ... that's why ep_enable() passes full
> endpoint configs (as descriptors), so they can more easily be changed.
>
> If the notion is that there are values that may need to get passed from
> silicon to driver, I'd like to see that done explicitly, with drivers
> updating descriptors, instead of doing anything by back-door routes
> that make UDC drivers making hidden updates.
>
> - Dave

This implementation creates default SuperSpeed descriptors with default
values. It is used to spare drivers that don't want to fully exploit
SuperSpeed functionality from handling SupperSpeed descriptors and still
be able to operate in a SupperSpeed mode.
Please note that the gadget driver can still provide SuperSpeed
descriptors with correct (and not default values) if it wishes to.
I hope I understood your comment correctly. Please let me know if this is
not the case.

>
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Sent by an consultant of the Qualcomm Innovation Center, Inc.
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