On Thu, Nov 03, 2016 at 12:50:43PM +0200, Felipe Balbi wrote:
>
> Hi,
>
> Peter Chen <hzpeterchen@xxxxxxxxx> writes:
> > 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.
>
> wMaxPacketSize && 0x7ff is always 1 unless wMaxPacketSize is zero, which
> is invalid anyway.
>
> >> >> > +
> >> >> > + 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.
>
> Logical vs Bitwise operator
>
Oh, my careless, I should read my patch again after getting your
comments. Test is ok not stands for code logic is ok.
round_up(3072,1) = 3072, so patch does not trigger error.
--
Best Regards,
Peter Chen
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