Re: [PATCH 1/2] usb: gadget: introduce flag for large request

[Macpaul Lin]

Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> æ 2020å6æ16æ éä äå10:05åéï
>
> On Tue, Jun 16, 2020 at 08:34:43PM +0800, Macpaul Lin wrote:
> > Some USB hardware like DMA engine can help to process (split) the data
> > of each URB request into small packets. For example, the max packet size
> > of high speed is 512 bytes. These kinds of hardware can help to split
> > the continue Tx/Rx data requests into packets just at the max packet
> > size during transmission. Hence upper layer software can reduce some
> > effort for queueing many requests back and forth for larger data.
> >
> > Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
> > hardware is ready to support these operations.
>
> This isn't needed.  All UDC drivers must be able to support requests that
> are larger than the maxpacket size.
>
> Alan Stern

Thanks for your reply, could we just modify the patch 2 (u_serial.c)
for improving
better performance? I'm not sure why there was a restriction about max packet.
Isn't there any historical reason?

-- 
Best regards,
Macpaul Lin