Hi, Peter Chen <[email protected]> writes: > On Thu, Nov 03, 2016 at 11:27:40AM +0200, Felipe Balbi wrote: >> >> Hi, >> >> Peter Chen <[email protected]> writes: >> >> Peter Chen <[email protected]> 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 <[email protected]> >> >> > Cc: Felipe Balbi <[email protected]> >> >> > Fixes: 16b114a6d797 ("usb: gadget: fix usb_ep_align_maybe >> >> > endianness and new usb_ep_aligna") >> >> > >> >> > Signed-off-by: Peter Chen <[email protected]> >> >> > --- >> >> > 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 -- balbi
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