Hi all,

On 24-08-08, kernel test robot wrote:

Hi Marco,

kernel test robot noticed the following build errors:

[auto build test ERROR on 0c3836482481200ead7b416ca80c68a29cfdaabd]

url:    https://github.com/intel-lab-lkp/linux/commits/Marco-Felsch/usb-hub-add-infrastructure-to-pass-onboard_dev-port-features/20240807-224100
base:   0c3836482481200ead7b416ca80c68a29cfdaabd
patch link:    https://lore.kernel.org/r/20240807-b4-v6-10-topic-usb-onboard-dev-v1-1-f33ce21353c9%40pengutronix.de
patch subject: [PATCH 1/3] usb: hub: add infrastructure to pass onboard_dev port features
config: i386-randconfig-141-20240808 (https://download.01.org/0day-ci/archive/20240808/202408081557.FiEe9Tzz-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240808/202408081557.FiEe9Tzz-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202408081557.FiEe9Tzz-lkp@intel.com/ (local)

All errors (new ones prefixed by >>):

   ld: drivers/usb/core/hub.o: in function `set_port_feature':

quoted

quoted

drivers/usb/core/hub.c:481: undefined reference to `onboard_dev_port_feature'

   ld: drivers/usb/core/hub.o: in function `usb_clear_port_feature':
   drivers/usb/core/hub.c:462: undefined reference to `onboard_dev_port_feature'

I understood the isse but have a few questions. Before continue the work
on this topic I would like to ask if the patchset is okay in general?
I'm open for alternatives if the patchset approach is not okay.

I have a few ideas in mind (see below) to fix the 0day build issue which
was caused by the Kconfig selection:

 - CONFIG_USB=y
 - CONFIG_USB_ONBOARD_DEV=m.

Idea-1:
-------

Dropping the module support for CONFIG_USB_ONBOARD_DEV.

Idea-2:
-------

CONFIG_USB_ONBOARD_DEV follows CONFIG_USB:

CONFIG_USB=y -> CONFIG_USB_ONBOARD_DEV=y,
CONFIG_USB=m -> CONFIG_USB_ONBOARD_DEV=m.

and exporting usb_clear_port_feature().

I don't know to add such Kconfig dependency and also this idea require
that the usbcore have to load the usb_onboard_dev module always,
regardless if used.

So this idea is rather suboptimal.

Idea-3:
-------

Adding a function to the hub.c usbcore which can be used by the
usb-onboard-dev driver to register this function as hook. This removes
the dependency from the core and the usb-onboard-dev module is only
pulled if really required. Of course this require that the hub.c usbcore
driver allows custom hooks.

Idea-X:
-------

I'm open for your input :)


Regards,
  Marco

PS: My favourite is Idea-3 followed by Idea-1.

vim +481 drivers/usb/core/hub.c

   466	
   467	/*
   468	 * USB 2.0 spec Section 11.24.2.13
   469	 */
   470	static int set_port_feature(struct usb_device *hdev, int port1, int feature)
   471	{
   472		int ret;
   473	
   474		ret = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
   475			USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port1,
   476			NULL, 0, 1000);
   477		if (ret)
   478			return ret;
   479	
   480		if (!is_root_hub(hdev))
 > 481			ret = onboard_dev_port_feature(hdev, true, feature, port1);
   482	
   483		return ret;
   484	}
   485	

-- 
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https://github.com/intel/lkp-tests/wiki