Re: linux 4.2-rc1 broken Nokia N900

[Sebastian Reichel <sre@kernel.org>]

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Hi,

On Wed, Jul 22, 2015 at 09:27:32AM +0200, Pali Rohár wrote:
> > > diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> > > index 5867384..f7d9ffd 100644
> > > --- a/drivers/spi/spi-omap2-mcspi.c
> > > +++ b/drivers/spi/spi-omap2-mcspi.c
> > > @@ -245,6 +245,7 @@ static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
> > >  
> > >  static void omap2_mcspi_set_cs(struct spi_device *spi, bool enable)
> > >  {
> > > +       struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);
> > >         u32 l;
> > >  
> > >         /* The controller handles the inverted chip selects
> > > @@ -255,6 +256,8 @@ static void omap2_mcspi_set_cs(struct spi_device *spi, bool enable)
> > >                 enable = !enable;
> > >  
> > >         if (spi->controller_state) {
> > > +               pm_runtime_get_sync(mcspi->dev);
> > > +
> > 
> > Should the return code should be checked here as with the other
> > instances of pm_runtime_get_sync?

Yes. If it fails, the line fetch error would be triggered again.

Probably the set_cs callback should also be changed, so that it can
return an error code. This is not something for 4.2-rc, though.

> Anyway, what do you think about adding gcc macro for pm_runtime_get_sync
> function which report compiler warning when return value is not checked?

Adding __must_check to pm_runtime_get_sync() should be discussed
separately with the relevant people in Cc. A quick grep in drivers/
reveals a huge amount of code not handling pm_runtime_get_sync's return
code.

-- Sebastian

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