On Mon, 19 Dec 2016 14:56:00 -0600 Bin Liu <b-liu@xxxxxx> wrote: > On Fri, Dec 16, 2016 at 07:19:39PM -0500, Jérémy Lefaure wrote: > > When CONFIG_PM_SLEEP is disabled, SIMPLE_DEV_PM_OPS does not use > > bfin_resume and bfin_suspend even if CONFIG_PM is enabled: > > > > drivers/usb/musb/blackfin.c:602:12: warning: ‘bfin_resume’ defined but > > not used [-Wunused-function] > > static int bfin_resume(struct device *dev) > > ^~~~~~~~~~~ > > drivers/usb/musb/blackfin.c:585:12: warning: ‘bfin_suspend’ defined but > > not used [-Wunused-function] > > static int bfin_suspend(struct device *dev) > > ^~~~~~~~~~~~ > > > > The preprocessor condition should be on CONFIG_PM_SLEEP, not on CONFIG_PM. > > However it is better to mark these functions as __maybe_unused. > > Based on discussion in [1], __may_be_unused adds unnecessary image size, > right? > > [1] http://www.spinics.net/lists/linux-usb/msg149994.html > Hi Bin, I made my own tests and I think that __maybe_unused does not add unnecessary image size in our case. When I compile with CONFIG_PM_SLEEP disabled with or without this patch, the sections of both blackfin.o have the same size (I used with readelf -S). I think that the compiler discards the unused functions and the __maybe_unused stuff only tells to the compiler to not raise a warning. Furthermore, the coding style [1] recommends to use __maybe_unused to fix this kind of warning. [1]https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?id=refs/tags/v4.10-rc1#n1009 Regards, Jérémy > Regards, > -Bin. > > > > > Signed-off-by: Jérémy Lefaure <jeremy.lefaure@xxxxxxxxxxxx> > > --- > > drivers/usb/musb/blackfin.c | 6 ++---- > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/usb/musb/blackfin.c b/drivers/usb/musb/blackfin.c > > index 310238c6b5cd..f43edc43268b 100644 > > --- a/drivers/usb/musb/blackfin.c > > +++ b/drivers/usb/musb/blackfin.c > > @@ -580,8 +580,7 @@ static int bfin_remove(struct platform_device *pdev) > > return 0; > > } > > > > -#ifdef CONFIG_PM > > -static int bfin_suspend(struct device *dev) > > +static int __maybe_unused bfin_suspend(struct device *dev) > > { > > struct bfin_glue *glue = dev_get_drvdata(dev); > > struct musb *musb = glue_to_musb(glue); > > @@ -598,7 +597,7 @@ static int bfin_suspend(struct device *dev) > > return 0; > > } > > > > -static int bfin_resume(struct device *dev) > > +static int __maybe_unused bfin_resume(struct device *dev) > > { > > struct bfin_glue *glue = dev_get_drvdata(dev); > > struct musb *musb = glue_to_musb(glue); > > @@ -607,7 +606,6 @@ static int bfin_resume(struct device *dev) > > > > return 0; > > } > > -#endif > > > > static SIMPLE_DEV_PM_OPS(bfin_pm_ops, bfin_suspend, bfin_resume); > > > > -- > > 2.11.0 > > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
