Re: [PATCH 2/3] PWM: vt8500: Update vt8500 PWM driver support

From: Thierry Reding
Date: Mon Oct 22 2012 - 11:08:56 EST


On Mon, Oct 22, 2012 at 01:52:08PM +0000, Arnd Bergmann wrote:
> On Monday 22 October 2012, Thierry Reding wrote:
> > > As long as we get build warnings for leaving out the __devinit/__devexit
> > > annotations, I would generally recommend putting them in. If we do a
> > > patch to remove all of them, a couple extra instances will not cause
> > > any more troubles than we already have.
> >
> > I've never seen any build warnings for leaving __devinit/__devexit out.
> > Where does that happen?
>
> Section mismatches usually result into warnings from modpost, like
>
> WARNING: modpost: Found 1 section mismatch(es).
> To see full details build your kernel with:
> 'make CONFIG_DEBUG_SECTION_MISMATCH=y'
>
> Actually doing that gives you an output like this (currently on exynos_defconfig):
>
> $ make CONFIG_DEBUG_SECTION_MISMATCH=y
> WARNING: drivers/pinctrl/built-in.o(.devinit.text+0x124): Section mismatch in reference from the function samsung_pinctrl_probe() to the function .init.text:samsung_gpiolib_register()
> The function __devinit samsung_pinctrl_probe() references
> a function __init samsung_gpiolib_register().
> If samsung_gpiolib_register is only used by samsung_pinctrl_probe then
> annotate samsung_gpiolib_register with a matching annotation.
>
> or like this (now fixed in socfpga_defconfig):
>
> WARNING: drivers/net/ethernet/stmicro/stmmac/stmmac.o(.text+0x5d4c): Section mismatch in reference from the function stmmac_pltfr_probe() to the function .devinit.text:stmmac_probe_config_dt()
> The function stmmac_pltfr_probe() references
> the function __devinit stmmac_probe_config_dt().
> This is often because stmmac_pltfr_probe lacks a __devinit
> annotation or the annotation of stmmac_probe_config_dt is wrong.
>
> I believe you normally don't get warnings for functions that could be
> marked __devinit and only call regular functions, but there are
> a couple of __devinit infrastructure functions that you can't call
> from a function that isn't __init or __devinit.

Right. If you get those warnings you shouldn't be dropping the
annotations. But I don't think that is the case for this driver. Tony,
can you confirm that the driver still builds properly without warnings
if you drop the __devinit/__devexit?

Thierry

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