Re: [PATCH 09/13] cpufreq: acpi-cpufreq: Remove unused ID structs

From: Viresh Kumar
Date: Tue Jul 14 2020 - 23:27:24 EST


On 15-07-20, 08:54, Viresh Kumar wrote:
> On 14-07-20, 22:03, Lee Jones wrote:
> > On Tue, 14 Jul 2020, Rafael J. Wysocki wrote:
> >
> > > On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> > > >
> > > > Can't see them being used anywhere and the compiler doesn't complain
> > > > that they're missing, so ...
> > >
> > > Aren't they needed for automatic module loading in certain configurations?
> >
> > Any idea how that works, or where the code is for that?
>
> The MODULE_DEVICE_TABLE() thingy creates a map of vendor-id,
> product-id that the kernel keeps after boot (and so there is no static
> reference of it for the compiler), later when a device is hotplugged
> into the kernel it refers to the map to find the related driver for it
> and loads it if it isn't already loaded.
>
> This has some of it, search for MODULE_DEVICE_TABLE() in it.
> Documentation/driver-api/usb/hotplug.rst

And you just need to add __maybe_unused to them to suppress the
warning.

--
viresh