On Wed, Oct 30, 2013 at 01:31:50PM -0400, Alan Stern wrote:
> On Wed, 30 Oct 2013, David Cohen wrote:
>
> > Due to USB controllers may have different restrictions, usb gadget layer
> > needs to provide a generic way to inform gadget functions to complain
> > with non-standard requirements.
> >
> > This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
> > to inform when controller's epout requires buffer size to be aligned to
> > MaxPacketSize.
> >
> > Signed-off-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
> > ---
> > include/linux/usb/gadget.h | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> > index 942ef5e..9405d0f 100644
> > --- a/include/linux/usb/gadget.h
> > +++ b/include/linux/usb/gadget.h
> > @@ -540,6 +540,9 @@ struct usb_gadget {
> > struct device dev;
> > unsigned out_epnum;
> > unsigned in_epnum;
> > +
> > + /* epout requires buffer size to be aligned to MaxPacketSize */
> > + unsigned quirk_ep_out_aligned_size:1;
> > };
> > #define work_to_gadget(w) (container_of((w), struct usb_gadget, work))
>
> Instead of adding this new bitflag to the end of the structure, where
> it will cause the structure to grow by at least 4 bytes, why not add it
> in the middle, along with all the other bitflags, where it won't cause
> any change in the structure's size?
>
> If you prefer, you can move the name, dev, out_epnum, and in_epnum
> fields higher up, so that the bitflags come last.
I'd prefer moving the fields and having all bit-fields, last. Thanks
--
balbi
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