On Thu, Nov 03, 2016 at 11:27:40AM +0200, Felipe Balbi wrote:
>
> Hi,
>
> Peter Chen <hzpeterchen@xxxxxxxxx> writes:
> >> Peter Chen <peter.chen@xxxxxxx> writes:
> >> > For isoc endpoint descriptor, the wMaxPacketSize is not real max packet
> >> > size (see Table 9-13. Standard Endpoint Descriptor, USB 2.0 specifcation),
> >> > it may contain the number of packet, so the real max packet should be
> >> > ep->desc->wMaxPacketSize && 0x7ff.
> >> >
> >> > Cc: Felipe F. Tonello <eu@xxxxxxxxxxxxxxxxx>
> >> > Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
> >> > Fixes: 16b114a6d797 ("usb: gadget: fix usb_ep_align_maybe
> >> > endianness and new usb_ep_aligna")
> >> >
> >> > Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> >> > ---
> >> > include/linux/usb/gadget.h | 5 ++++-
> >> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >> >
> >> > diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> >> > index 8e81f9e..cce2db6 100644
> >> > --- a/include/linux/usb/gadget.h
> >> > +++ b/include/linux/usb/gadget.h
> >> > @@ -429,7 +429,10 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
> >> > */
> >> > static inline size_t usb_ep_align(struct usb_ep *ep, size_t len)
> >> > {
> >> > - return round_up(len, (size_t)le16_to_cpu(ep->desc->wMaxPacketSize));
> >> > + int max_packet_size = (size_t)le16_to_cpu(ep->desc->wMaxPacketSize)
> >> > + && 0x7ff;
> ^^
> hehe, I just noticed this bug. Did you really test this patch? :-)
>
Any problems you find? Without this patch, the usbtest can't be ran
for high bandwidth isoc transfer.
> >> > +
> >> > + return round_up(len, max_packet_size);
> >> > }
> >>
> >> care to update this to use new usb_endpoint_maxp()?
> >>
> >
> > But it is a bug existed at v4.9, the usb_ep_align returns wrong request
> > length for isoc. I found this bug by running usbtest.
>
> keep your & (after fixing it), but use usb_endpoint_maxp(). Later we can
> just remove the unnecessary & operation.
>
> --
> balbi
I will use usb_endpoint_maxp, but I still not find the problem for this
patch.
--
Best Regards,
Peter Chen
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