[v1] USB: cdc-acm: Fix bit overlap and move quirk definitions to header

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

Posted by Wentao Guan 1 month, 1 week ago

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
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
---
 drivers/usb/class/cdc-acm.c | 2 --
 drivers/usb/class/cdc-acm.h | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index c024011dc336a..d64751c42c2bc 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -114,8 +114,6 @@ static int acm_ctrl_msg(struct acm *acm, int request, int value,
 	int retval;
 
 	retval = usb_autopm_get_interface(acm->control);
-#define VENDOR_CLASS_DATA_IFACE		BIT(9)  /* data interface uses vendor-specific class */
-#define ALWAYS_POLL_CTRL		BIT(10) /* keep ctrl URB active even without an open TTY */
 	if (retval)
 		return retval;
 
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 25fd5329a8781..01f448a783c03 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -115,3 +115,5 @@ struct acm {
 #define DISABLE_ECHO			BIT(7)
 #define MISSING_CAP_BRK			BIT(8)
 #define NO_UNION_12			BIT(9)
+#define VENDOR_CLASS_DATA_IFACE		BIT(10)  /* data interface uses vendor-specific class */
+#define ALWAYS_POLL_CTRL		BIT(11) /* keep ctrl URB active even without an open TTY */
-- 
2.30.2

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

Posted by Greg KH 3 weeks, 2 days ago

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"?

thanks,

greg k-h

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

Posted by Wentao Guan 3 weeks, 2 days ago

> 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.

BRs
Wentao Guan

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

Posted by Greg KH 3 weeks, 1 day ago

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 :)