Re: [PATCH v3 04/11] HID: haptic: introduce hid_haptic_device

[Randy Dunlap <rdunlap@infradead.org>]

Hi,

On 10/9/25 7:43 AM, Thorsten Leemhuis wrote:
> On 8/19/25 01:08, Jonathan Denose wrote:
>> From: Angela Czubak <aczubak@google.com>
>>
>> Define a new structure that contains simple haptic device configuration
>> as well as current state.
>> Add functions that recognize auto trigger and manual trigger reports
>> as well as save their addresses.Hi,
>> Verify that the pressure unit is either grams or newtons.
>> Mark the input device as a haptic touchpad if the unit is correct and
>> the reports are found.
>>  [...]
>> +config HID_HAPTIC
>> +	tristate "Haptic touchpad support"
>> +	default n
>> +	help
>> +	Support for touchpads with force sensors and haptic actuators instead of a
>> +	traditional button.
>> +	Adds extra parsing and FF device for the hid multitouch driver.
>> +	It can be used for Elan 2703 haptic touchpad.
>> +
>> +	If unsure, say N.
>> +
>>  menu "Special HID drivers"
> 
> I suspect this change is related to a build error I ran into today:
> 
>   MODPOST Module.symvers
> ERROR: modpost: "hid_haptic_init" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_pressure_increase" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_check_pressure_unit" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_input_configured" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_input_mapping" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_feature_mapping" [drivers/hid/hid-multitouch.ko] undefined!
> ERROR: modpost: "hid_haptic_pressure_reset" [drivers/hid/hid-multitouch.ko] undefined!
> make[3]: *** [/home/thl/var/linux.dev/scripts/Makefile.modpost:147: Module.symvers] Error 1
> 
> The config where this occurred had this:
> 
> CONFIG_HID=y
> CONFIG_HID_MULTITOUCH=m
> CONFIG_HID_HAPTIC=m
> 
> Changing the latter to "CONFIG_HID_HAPTIC=y" fixed the problem for me.

Sure, but that's just covering up the problem.

First, I get this build error:

ERROR: modpost: missing MODULE_LICENSE() in drivers/hid/hid-haptic.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/hid/hid-haptic.o

so I added those to hid-haptic.c.... and I still get that same build error.

So I looked at the hid-haptic.o file, in the .modinfo section,
and saw this:

Disassembly of section .modinfo:

0000000000000000 <__UNIQUE_ID_modinfo569>:
   0:	68 69 64 2e 6c       	push   $0x6c2e6469
   5:	69 63 65 6e 73 65 3d 	imul   $0x3d65736e,0x65(%rbx),%esp
   c:	47 50                	rex.RXB push %r8
   e:	4c 00            	rex.WR add %r13b,0x69(%rax)

which is ASCII " h  i  d  .  l  i  c  e  n  s  e  =  G  P  L".

so the license string is there.

Maybe something is modpost is having a problem.
Unless someone who has modified modpost recently has any ideas,
this needs a git bisect, I expect.

---
~Randy