From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Mon, 15 Feb 2016 10:20:49 +0100 Subject: [PATCH] iio: health/afe4403: mark suspend/resume functions __maybe_unused In-Reply-To: References: <1455526993-2132098-1-git-send-email-arnd@arndb.de> Message-ID: <3204595.MT2N1UgYF8@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Monday 15 February 2016 11:18:20 Daniel Baluta wrote: > On Mon, Feb 15, 2016 at 11:02 AM, Arnd Bergmann wrote: > > The newly added afe4403 driver implements suspend/resume using the > > SIMPLE_DEV_PM_OPS() macro, which leaves out references to the actual > > functions when CONFIG_PM is disabled, causing a harmless warning: > > > > health/afe4403.c:509:12: error: 'afe4403_suspend' defined but not used > > health/afe4403.c:530:12: error: 'afe4403_resume' defined but not used > > > > This marks the functions as __maybe_unused so we don't get those > > warnings. > > > Or we could put _suspend and _resume under CONFIG_PM_SLEEP. That never works reliably. I still have a backlog of ~50 patches of drivers that got this wrong in the past. > We have: > > :~/w/iio/drivers/iio$ ack-grep SIMPLE_DEV_PM_OPS | wc -l > 31 > > and only 2 drivers using __maybe_unused. > > :~/w/iio/drivers/iio$ ack-grep maybe_unused > gyro/itg3200_core.c > 354:static int __maybe_unused itg3200_suspend(struct device *dev) > 365:static int __maybe_unused itg3200_resume(struct device *dev) > > adc/imx7d_adc.c > 553:static int __maybe_unused imx7d_adc_suspend(struct device *dev) > 566:static int __maybe_unused imx7d_adc_resume(struct device *dev) > > For consistency, we should use CONFIG_PM_SLEEP and get rid of __maybe_unused. I hope to eventually kill off all the CONFIG_PM_SLEEP checks and then make it work automatically by redefining SIMPLE_DEV_PM_OPS so it leaves an unused reference to the functions. Arnd