lkml.org 
[lkml]   [2016]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 06/14] dma: sirf: use __maybe_unused to hide pm functions
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

\
 
 \ /
  Last update: 2016-03-04 16:21    [W:0.066 / U:0.196 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site