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Re: [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions

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On Thu, Mar 03, 2016 at 01:33:17PM +0100, Arnd Bergmann wrote:
> On Thursday 03 March 2016 09:17:31 Vinod Koul wrote:
> > On Wed, Mar 02, 2016 at 04:58:58PM +0100, Arnd Bergmann wrote:
> > > The sirf dma driver uses #ifdef to check for CONFIG_PM_SLEEP
> > > for its suspend/resume code but then has no #ifdef for the
> > > respective runtime PM code, so we get a warning if CONFIG_PM
> > > is disabled altogether:
> > > 
> > > drivers/dma/sirf-dma.c:1000:12: error: 'sirfsoc_dma_runtime_resume' defined but not used [-Werror=unused-function]
> > > 
> > > This removes the existing #ifdef and instead uses __maybe_unused
> > > annotations for all four functions to let the compiler know it
> > > can silently drop the function definition.
> > 
> > Hi Arnd,
> > 
> > Rather than telling compiler that this maybe used why not add ifdef for it's
> > suspend/resume as well, what are the demerits of that approach?
> > 
> 
> As I tried to explain in the cover letter, everyone gets the #ifdef
> wrong, and the __maybe_unused annotation is harder to get wrong here.
> 
> This particular driver illustrates that well: sirfsoc_dma_remove()
> calls sirfsoc_dma_runtime_suspend(), so we must hide the
> resume function, but not suspend, and that is counterintuitive.
> 
> Other drivers have other problems, e.g. functions that get called
> only from within the sections under an #ifdef, and then those
> need the same #ifdef added, which gets even more complicated when
> you have both runtime-pm and suspend support.

Thanks, applied now after fixing subsystem name

-- 
~Vinod

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[PATCH 00/14] drivers: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
  [PATCH 12/14] keyboard: snvs-pwrkey: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    RE: [PATCH 12/14] keyboard: snvs-pwrkey: use __maybe_unused to hide  pm functions Frank Li <frank.li@nxp.com> - 2016-03-02 17:40 +0100
      Re: [PATCH 12/14] keyboard: snvs-pwrkey: use __maybe_unused to hide  pm functions Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-03-02 18:20 +0100
  [PATCH 03/14] power: ipaq-micro-battery: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 03/14] power: ipaq-micro-battery: use __maybe_unused to  hide pm functions Sebastian Reichel <sre@kernel.org> - 2016-03-03 15:30 +0100
  [PATCH 10/14] wireless: cw1200: use __maybe_unused to hide pm functions_ Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [10/14] wireless: cw1200: use __maybe_unused to hide pm functions_ Kalle Valo <kvalo@codeaurora.org> - 2016-03-08 11:40 +0100
  [PATCH 11/14] input: spear-keyboard: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 11/14] input: spear-keyboard: use __maybe_unused to hide  pm functions Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-03-02 18:20 +0100
  Re: [PATCH 01/14] pinctrl: at91: use __maybe_unused to hide pm  functions Nicolas Ferre <nicolas.ferre@atmel.com> - 2016-03-02 17:10 +0100
  [PATCH 13/14] [media] omap3isp: use IS_ENABLED() to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
  [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions Vinod Koul <vinod.koul@intel.com> - 2016-03-03 04:50 +0100
      Re: [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-03 13:40 +0100
        Re: [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions Vinod Koul <vinod.koul@intel.com> - 2016-03-04 16:00 +0100
  [PATCH 01/14] pinctrl: at91: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 01/14] pinctrl: at91: use __maybe_unused to hide pm  functions Ludovic Desroches <ludovic.desroches@atmel.com> - 2016-03-02 17:50 +0100
    Re: [PATCH 01/14] pinctrl: at91: use __maybe_unused to hide pm functions Linus Walleij <linus.walleij@linaro.org> - 2016-03-09 05:10 +0100
  [PATCH 09/14] amd-xgbe: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
  [PATCH 04/14] power: pm2301-charger: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 04/14] power: pm2301-charger: use __maybe_unused to hide  pm functions Sebastian Reichel <sre@kernel.org> - 2016-03-03 15:30 +0100
  [PATCH 14/14] ASoC: rockchip: use __maybe_unused to hide st_irq_syscfg_resume Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
  [PATCH 08/14] scsi: mvumi: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 08/14] scsi: mvumi: use __maybe_unused to hide pm  functions Johannes Thumshirn <jthumshirn@suse.de> - 2016-03-03 09:40 +0100
    Re: [PATCH 08/14] scsi: mvumi: use __maybe_unused to hide pm functions "Martin K. Petersen" <martin.petersen@oracle.com> - 2016-03-05 23:10 +0100
  [PATCH 02/14] irqchip: st: use __maybe_unused to hide st_irq_syscfg_resume Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
  [PATCH 07/14] hw_random: exynos: use __maybe_unused to hide pm functions Arnd Bergmann <arnd@arndb.de> - 2016-03-02 17:10 +0100
    Re: [PATCH 07/14] hw_random: exynos: use __maybe_unused to hide pm  functions Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-03-03 00:50 +0100
    Re: [PATCH 07/14] hw_random: exynos: use __maybe_unused to hide pm  functions Herbert Xu <herbert@gondor.apana.org.au> - 2016-03-11 14:40 +0100

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