Re: IIO_BUFFER - IIO_TRIGGERED_BUFFER circular dependency

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Mar 01, 2013 at 02:38:30PM +0100, Lars-Peter Clausen wrote:
> On 03/01/2013 05:32 AM, Guenter Roeck wrote:
> > Hi all,
> > 
> > IIO_TRIGGERED_BUFFER depends on IIO_BUFFER because of:
> > 
> > drivers/iio/industrialio-triggered-buffer.c:20:16: error:
> > ‘iio_sw_buffer_preenable’ undeclared here (not in a function)
> > 
> > On the other side, it is often selected as follows.
> > 
> > 	select IIO_TRIGGERED_BUFFER if (IIO_BUFFER)
> > 
> > For that reason, selecting IIO_BUFFER in the IIO_TRIGGERED_BUFFER declaration
> > results in a circular dependency. Sometimes the "if (IIO_BUFFER)" when selecting
> > IIO_TRIGGERED_BUFFER is missing, though, which can result in the compile error.
> > 
> > What is the proper solution ?
> > - Add "if (IIO_BUFFER)" whenever IIO_TRIGGERED_BUFFER is selected
> > or
> > - Remove "if (IIO_BUFFER)" from IIO_TRIGGERED_BUFFER selection and add "select
> >   IIO_BUFFER" to the IIO_TRIGGERED_BUFFER declaration
> > 
> > I would prefer the latter to solve the problem for good.
> 
> Hi,
> 
> This is a bit tricky, some drivers have optional buffer support, so they
> only select the helper module if buffer support is enabled, since they don't
> use the helper module if buffer support is disabled. Other driver though
> always want buffer support so they select the helper module unconditionally.
> So far it was the responsibility of the driver's Kconfig entry to make sure
> that if it selects IIO_TRIGGERED_BUFFER it needs to make sure that
> IIO_BUFFER is also selected. As far as I can see all drivers do this
> currently. Which one breaks things for you?
> 
It is a randconfig thing, so it breaks in some of my nightly randconfig builds,
and it has also been reported as build failure in the official builds. I can dig
out some affected configurations and send it to you if you like, but the gist of
it is that IIO_TRIGGERED_BUFFER can be selected without IIO_BUFFER, but depends
on it. That just isn't correct. Of course, the other option might be to make
IIO_TRIGGERED_BUFFER dependent on IIO_BUFFER. Would that be acceptable ?

Thanks,
Guenter
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Input]     [Linux Kernel]     [Linux SCSI]     [X.org]

  Powered by Linux