On Wed, Mar 27, 2024 at 1:18 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> On 3/27/24 12:05 PM, Andy Shevchenko wrote:
> > On Wed, Mar 27, 2024 at 9:58 AM Kate Hsuan <hpa@xxxxxxxxxx> wrote:
> >> On Mon, Mar 25, 2024 at 3:30 AM Andy Shevchenko
> >> <andy.shevchenko@xxxxxxxxx> wrote:
> >>> On Sun, Mar 24, 2024 at 5:02 PM Kate Hsuan <hpa@xxxxxxxxxx> wrote:
...
> >>>> +static int __init xiaomi_mipad2_init(void)
> >>>> +{
> >>>> + return software_node_register_node_group(ktd2026_node_group);
> >>>> +}
> >>>> +
> >>>> +static void xiaomi_mipad2_exit(void)
> >>>
> >>> __exit ?
> >> No need.
> >> x86-andriod-tablet is based on platform_driver and platform_device so
> >> it doesn't need __exit.
> >>
> >> I put __exit and the compiler complained about the warning.
> >> ===
> >> WARNING: modpost:
> >> drivers/platform/x86/x86-android-tablets/x86-android-tablets: section
> >> mismatch in reference: xiaomi_mipad2_info+0x50 (section: .init.rodata)
> >> -> xiaomi_mipad2_exit (section: .exit.text)
> >> ===
> >
> > This is interesting. Why then do we call them symmetrically?
> >
> > Hans, do we need to have anything here been amended?
>
> No this is all as expected.
>
> The platform driver's probe() function can be __init because
> the platform device is registered with the special:
> platform_create_bundle() function which takes a probe() function
> and the actual "struct platform_driver" does not have .probe
> set at all.
>
> Since we need to do manual cleanup on remove() however we need
> a remove() callback and that does sit in the struct platform_driver
> and since remove() can normally also be called on manual unbind
> of the driver through sysfs it cannot be in the __exit section.
>
> I say normally because IIRC platform_create_bundle() disables
> manual unbinding but the section checking code does not know this,
> all it sees is that the "struct platform_driver" is not __exit
> and that it references the remove() callback and therefor the
> remove() callback itself cannot be __exit.
Thank you for the detailed explanation!
--
With Best Regards,
Andy Shevchenko
