[LAU] can't compile realtime kernel: error: conflicting types for ‘irqreturn_t’

[Jörn Nettingsmeier]

Dietrich Bollmann wrote:
> Hi,
> 
> Since some time I can't build the vanilla kernel when patching it with
> Ingo Molnar's realtime patch.
> 
> Any idea what is going wrong?
> 
> Thanks, Dietrich
> 
> Kernel:   http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.29.2.tar.bz2
> RT patch:
> http://www.kernel.org/pub/linux/kernel/projects/rt/patch-2.6.29.2-rt11.bz2
> 
> The compile error:
> 
>   [...]
>   LD [M]  drivers/ssb/ssb.o
>   CC [M]  drivers/staging/at76_usb/at76_usb.o
>   CC [M]  drivers/staging/comedi/comedi_fops.o
> In file included from drivers/staging/comedi/comedidev.h:40,
>                  from drivers/staging/comedi/comedi_fops.c:45:
> drivers/staging/comedi/interrupt.h:27: error: conflicting types for
> ‘irqreturn_t’
> include/linux/irqreturn.h:14: error: previous declaration of
> ‘irqreturn_t’ was here
> In file included from drivers/staging/comedi/comedidev.h:40,
>                  from drivers/staging/comedi/comedi_fops.c:45:
> drivers/staging/comedi/interrupt.h:30:1: warning: "IRQ_RETVAL" redefined
> In file included from include/linux/interrupt.h:10,
>                  from drivers/staging/comedi/interrupt.h:22,
>                  from drivers/staging/comedi/comedidev.h:40,
>                  from drivers/staging/comedi/comedi_fops.c:45:

the giveaway here is *staging*, or, as greg kh has it, "crap". nothing
in staging is needed (or should even be considered) for serious kernels.
why it's built by default in your setup is beyond me (never happened to
me), but i'm pretty sure you pressed some big red button during kernel
configuraton... it was probably even labelled "don't press this button
again".