[U-Boot] [UBOOT RFC PATCH 07/13] usb: gadget: g_dnl: Explicitly set the max packet size in descriptor

Felipe Balbi
2014-08-19T15:44:02Z

On Tue, Aug 19, 2014 at 09:08:00PM +0530, Kishon Vijay Abraham I wrote:
>
>
> On Monday 18 August 2014 08:26 PM, Lukasz Majewski wrote:
> > Hi Kishon,
> >
> >>> Explicity set the max packet size in the device descriptor to 0x40
> >>> as specified in the device class specification for device firmware
> >>> upgrade. Also changed debug to printf to explicitly notify the user
> >>> if the device has been enumerated.
> >
> > It seems like this patch slipped without my attention ...
> >
> > Hence, I'd like to ask why you must hardcode the packet size here?
>
> http://www.usb.org/developers/devclass_docs/usbdfu10.pdf (in section 4.2.1 DFU
> Mode Device Descriptor), specifies the bMaxPacketSize0 can be 8,16,32,64. And
> the value we get from gadget is 512. So hard coded it.

as I mentioned, this should be changed on connection done interrupt. DFU
has one of the poorest documentations for a USB Class and has some
moronic definitions. What happens if you want ot run DFU with a
superspeed controller (such as dwc3) when connected to a superspeed
port. We cannot use ep0 packet size as 64, right ? That's why hardcoding
is bad ;-)

--
balbi
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