Re: [PATCH v7] usb: common: usb-conn-gpio: Set last role to unknown before initial detection

[Prashanth K]

On 15-06-23 03:00 pm, Greg Kroah-Hartman wrote:
> On Wed, Jun 14, 2023 at 12:14:08PM +0300, Heikki Krogerus wrote:
> > On Wed, May 31, 2023 at 08:11:14PM +0530, Prashanth K wrote:
> > > Currently if we bootup a device without cable connected, then
> > > usb-conn-gpio won't call set_role() since last_role is same as
> > > current role. This happens because during probe last_role gets
> > > initialised to zero.
> > >
> > > To avoid this, added a new constant in enum usb_role, last_role
> > > is set to USB_ROLE_UNKNOWN before performing initial detection.
> > >
> > > While at it, also handle default case for the usb_role switch
> > > in cdns3, intel-xhci-usb-role-switch & musb/jz4740 to avoid
> > > build warnings.
> > >
> > > Fixes: 4602f3bff266 ("usb: common: add USB GPIO based connection detection driver")
> > > Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> > > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> > > ---
> > > v7: Added default case in musb/jz4740.c & intel-xhci-usb-role-switch.c to
> > >      avoid build warnings.
> > > v6: Moved USB_ROLE_UNKNOWN towards the end of enum usb_role.
> > > v5: Update commit text to mention the changes made in cdns3 driver.
> > > v4: Added Reviewed-by tag.
> > > v3: Added a default case in drivers/usb/cdns3/core.c as pointed out by
> > >      the test robot.
> > > v2: Added USB_ROLE_UNKNWON to enum usb_role.
> > >
> > >   drivers/usb/cdns3/core.c                       | 2 ++
> > >   drivers/usb/common/usb-conn-gpio.c             | 3 +++
> > >   drivers/usb/musb/jz4740.c                      | 2 ++
> > >   drivers/usb/roles/intel-xhci-usb-role-switch.c | 2 ++
> > >   include/linux/usb/role.h                       | 1 +
> > >   5 files changed, 10 insertions(+)
> >
> > Just to be clear to everybody, that USB_ROLE_UNKNOWN is not handled in
> > drivers/usb/roles/class.c, so this patch is broken.
> >
> > But the whole approach is wrong. That USB_ROLE_UNKNOWN is clearly a
> > flag where the other values in enum usb_role are actual switch states.
> > So it does not belong there.
> >
> > In general, adding globals states like that just in order to work
> > around issues in single drivers is never a good idea IMO.
>
> Ok, let me go revert this from my tree, thanks for the review.
>
> greg k-h

In that case, can I resubmit v1 of this patch again, where I have used a 
macro in usb-conn-gpio driver ? something like this.

@@ -27,6 +27,8 @@
 #define USB_CONN_IRQF	\
 	(IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)

+#define USB_ROLE_UNKNOWN (USB_ROLE_NONE -1)
+
 struct usb_conn_info {
 	struct device *dev;
 	struct usb_role_switch *role_sw;
@@ -257,6 +259,9 @@  static int usb_conn_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, info);
 	device_set_wakeup_capable(&pdev->dev, true);

+	/* Set last role to unknown before performing the initial detection */
+	info->last_role = USB_ROLE_UNKNOWN;
+
 	/* Perform initial detection */
 	usb_conn_queue_dwork(info, 0);

Thanks,
Prashanth K