On Fri, 14 Mar 2008, Rafael J. Wysocki wrote:
> On Friday, 14 of March 2008, Andrew Morton wrote:
> > Sorry, but that code should be dragged out and shot. Doing this:
> >
> > > device_can_wakeup(tty_dev) = 1;
> >
> > is just gross and stupid. It looks daft, it isn't C and it *requires* that
> > device_can_wakeup() be implemented as a macro, which totally busts any
> > concept of abstraction.
It seems to have been a one-time occurrence. This patch series fixes
it.
> > The code previously had quite reasonable accessors:
> >
> > #define device_set_wakeup_enable(dev,val) \
> > ((dev)->power.should_wakeup = !!(val))
> > #define device_may_wakeup(dev) \
> > (device_can_wakeup(dev) && (dev)->power.should_wakeup)
> >
> > can we please go back to that scheme? Please also convert all these
> > magical macros into inlined C functions. One reason is that this:
> >
> > +#define device_init_wakeup(dev,val) \
> > + do { \
> > + device_can_wakeup(dev) = !!(val); \
> > + device_set_wakeup_enable(dev,val); \
> > + } while(0)
> >
> > is buggy. It evaluates its arguments multiple times and will cause
> > failures when passed expressions which have side-effects.
This series converts the macros to inline functions.
> > Alan, please also pass all future patches through checkpatch - there is no
> > need to be adding trivial coding-style errors in this day and age.
Rest assurred that checkpath is now an integral part of my normal
workflow. All the patches in this series pass with flying colors.
> Well, Greg please drop the "PM: make wakeup flags available whenever CONFIG_PM
> is set" and Alan please resubmit the patch with the problems pointed out by
> Andrew fixed.
>
> In fact I'd even prefer it to be two patches, one that moves should_wakeup and
> the related macros out of the CONFIG_PM_SLEEP #ifdef, because that's what fixes
> the problem described in the changelog, and one that makes the remaining
> changes with a separate changelog.
Done.
The 1/3 patch fixes the unfortunate code in the serial-core driver.
The 2/3 patch moves the macros out from under CONFIG_PM_SLEEP.
The 3/3 patch converts the macros to inline functions and creates a new
pm_wakeup.h file for them. They can't remain in pm.h, because they
depend on the definition of struct device -- and the compiler hasn't
seen that yet when pm.h is read.
It's not clear why the can_wakeup accessors are written to work even
when CONFIG_PM isn't set. Nevertheless, the patches retain that
behavior.
Alan Stern
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