On Fri, Mar 01, 2013 at 06:41:11AM -0800, Guenter Roeck wrote: > 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 ? > Wait, that is already the case. So I guess to fix the problem, it will be necesary to change all instances of select IIO_TRIGGERED_BUFFER to select IIO_TRIGGERED_BUFFER if if (IIO_BUFFER) for instances where IIO_BUFFER is not also selected, or to also select IIO_BUFFER if the driver really needs it. Offender is INV_MPU6050_IIO, which does need IIO_BUFFER. I'll send a patch to fix that. 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
