Re: [PATCH RFC] USB: cdc-acm: Fix bit overlap and move quirk definitions to header

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, May 21, 2026 at 11:03:02PM +0800, Wentao Guan wrote:
> > On Wed, May 06, 2026 at 05:32:13PM +0800, Wentao Guan wrote:
> > > The VENDOR_CLASS_DATA_IFACE and ALWAYS_POLL_CTRL quirk flags added in
> > > commit f58752ebcb35 ("USB: cdc-acm: Add quirks for Yoga Book 9 14IAH10
> > > INGENIC touchscreen") were placed inside the acm_ctrl_msg() function
> > > rather than in the header with the other quirk flags.  Then, their
> > > values (BIT(9) and BIT(10)) collided with NO_UNION_12 which is already
> > > BIT(9).
> > >
> > > Move the definitions to drivers/usb/class/cdc-acm.h where they belong
> > > and shift them to BIT(10) and BIT(11) to avoid the overlap.
> > >
> > > Fixes: f58752ebcb35 ("USB: cdc-acm: Add quirks for Yoga Book 9 14IAH10 INGENIC touchscreen")
> > > Cc: stable@vger.kernel.org
> >
> > Why is this needed for stable?  What bug does this "fix"?
> I see that there is a bug that NO_UNION_12 and VENDOR_CLASS_DATA_IFACE use same bit.

Then send this as a non-RFC patch, as obviously we can not take RFC
patches :)