Re: [PATCH] [media] media: Kconfig: add dependency of HAS_DMA

From: Sakari Ailus
Date: Thu Jan 14 2016 - 03:47:10 EST

Hi Marek and Sudip,

On Wed, Jan 13, 2016 at 03:36:39PM +0100, Marek Szyprowski wrote:
> Hello,
> On 2016-01-12 15:10, Sakari Ailus wrote:
> >On Mon, Jan 11, 2016 at 06:23:11PM +0530, Sudip Mukherjee wrote:
> >>On Wed, Dec 30, 2015 at 06:56:03PM +0530, Sudip Mukherjee wrote:
> >>>The build of m32r allmodconfig fails with the error:
> >>>drivers/media/v4l2-core/videobuf2-dma-contig.c:484:2:
> >>> error: implicit declaration of function 'dma_get_cache_alignment'
> >>>
> >>>The build of videobuf2-dma-contig.c depends on HAS_DMA and it is
> >>>correctly mentioned in the Kconfig but the symbol VIDEO_STI_BDISP also
> >>>selects VIDEOBUF2_DMA_CONTIG, so it is trying to compile
> >>>videobuf2-dma-contig.c even though HAS_DMA is not defined.
> >>>
> >>>Signed-off-by: Sudip Mukherjee <sudip@xxxxxxxxxxxxxxx>
> >>>---
> >>A gentle ping. m32r allmodconfig still fails with next-20160111. Build
> >>log is at:
> >>
> >Hi Sudip,
> >
> >Even though the issue now manifests itself on m32r, the problem is wider
> >than that: dma_get_cache_alignment() is only defined if CONFIG_HAS_DMA is
> >set.
> >
> >I wonder if using videobuf2-dma-contig makes any sense if HAS_DMA is
> >disabled, so perhaps it'd be possible to make it depend on HAS_DMA.
> VIDEOBUF2_DMA_CONTIG already depends on HAS_DMA, but when driver use select
> directive for enabling support for VIDEOBUF2_DMA_CONTIG, the dependencies
> are not checked further. This is known limitation/feature of kconfig system.

Thanks for the insight. Sounds like this is the right thing to do then.

Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>

Kind regards,

Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx