On Thu, 7 Dec 2023 22:07:23 +0100
Armin Wolf <W_Armin@xxxxxx> wrote:
> It seems that when the driver is built-in, the HID bus is
> initialized after the driver is loaded, which whould cause
> module_hid_driver() to fail.
> Fix this by registering the driver after the HID bus using
> late_initcall() in accordance with other hwmon HID drivers.
>
> Compile-tested only.
So you did not test this? Well, I did.
[ 2.225831] Driver 'corsair-psu' was unable to register with bus_type 'hid' because the bus was not initialized.
[ 2.225835] amd_pstate: driver load is disabled, boot with specific mode to enable this
[ 2.226363] ledtrig-cpu: registered to indicate activity on CPUs
[ 2.226679] hid: raw HID events driver (C) Jiri Kosina
You are right, it is a timing issue and this can actually happen. I'm fine with
the fix.
Though, this could even be a bigger issue. There are currently 104 HID drivers
using the module_hid_driver macro. Maybe it would be a better idea to change the
module_hid_driver macro to use the lateinit calls instead of the plain init/exit
calls.
greetings,
Will
> Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> ---
> drivers/hwmon/corsair-psu.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
> index 904890598c11..2c7c92272fe3 100644
> --- a/drivers/hwmon/corsair-psu.c
> +++ b/drivers/hwmon/corsair-psu.c
> @@ -899,7 +899,23 @@ static struct hid_driver corsairpsu_driver = {
> .reset_resume = corsairpsu_resume,
> #endif
> };
> -module_hid_driver(corsairpsu_driver);
> +
> +static int __init corsair_init(void)
> +{
> + return hid_register_driver(&corsairpsu_driver);
> +}
> +
> +static void __exit corsair_exit(void)
> +{
> + hid_unregister_driver(&corsairpsu_driver);
> +}
> +
> +/*
> + * With module_init() the driver would load before the HID bus when
> + * built-in, so use late_initcall() instead.
> + */
> +late_initcall(corsair_init);
> +module_exit(corsair_exit);
>
> MODULE_LICENSE("GPL");
> MODULE_AUTHOR("Wilken Gottwalt <wilken.gottwalt@xxxxxxxxxx>");
> --
> 2.39.2
>
