[PATCH v4 1/7] usb: typec: Add default HPD device when register DisplayPort altmode

[kernel test robot]

Hi Chaoyi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next usb/usb-linus robh/for-next linus/master v6.17-rc7 next-20250919]
[cannot apply to rockchip/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chaoyi-Chen/usb-typec-Add-default-HPD-device-when-register-DisplayPort-altmode/20250922-092549
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20250922012039.323-2-kernel%40airkyi.com
patch subject: [PATCH v4 1/7] usb: typec: Add default HPD device when register DisplayPort altmode
config: i386-buildonly-randconfig-003-20250922 (https://download.01.org/0day-ci/archive/20250922/202509221516.1umvcXG6-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250922/202509221516.1umvcXG6-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 <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509221516.1umvcXG6-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/usb/typec/class.c:18:
>> drivers/usb/typec/altmodes/displayport.h:7:5: warning: no previous prototype for 'dp_altmode_probe' [-Wmissing-prototypes]
       7 | int dp_altmode_probe(struct typec_altmode *alt) { return -ENOTSUPP; }
         |     ^~~~~~~~~~~~~~~~
>> drivers/usb/typec/altmodes/displayport.h:8:6: warning: no previous prototype for 'dp_altmode_remove' [-Wmissing-prototypes]
       8 | void dp_altmode_remove(struct typec_altmode *alt) { }
         |      ^~~~~~~~~~~~~~~~~
>> drivers/usb/typec/altmodes/displayport.h:9:6: warning: no previous prototype for 'dp_altmode_hpd_device_register' [-Wmissing-prototypes]
       9 | void dp_altmode_hpd_device_register(struct typec_altmode *alt) { }
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/dp_altmode_probe +7 drivers/usb/typec/altmodes/displayport.h

d266e96820cc36 Ajay Gupta  2019-04-23 @7  int dp_altmode_probe(struct typec_altmode *alt) { return -ENOTSUPP; }
d266e96820cc36 Ajay Gupta  2019-04-23 @8  void dp_altmode_remove(struct typec_altmode *alt) { }
50d2edccce6bf3 Chaoyi Chen 2025-09-22 @9  void dp_altmode_hpd_device_register(struct typec_altmode *alt) { }

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