Re: [PATCH 06/13] v4l: vsp1: Disable cropping on WPF sink pad

[Mauro Carvalho Chehab <mchehab@s-opensource.com>]

Em Mon, 19 Sep 2016 21:33:13 +0300
Laurent Pinchart <laurent.pinchart@ideasonboard.com> escreveu:

> Hi Mauro,
> 
> On Monday 19 Sep 2016 15:26:15 Mauro Carvalho Chehab wrote:
> > Em Mon, 19 Sep 2016 20:59:56 +0300 Laurent Pinchart escreveu:  
> > > On Monday 19 Sep 2016 14:55:43 Mauro Carvalho Chehab wrote:  
> > >> Em Wed, 14 Sep 2016 02:16:59 +0300 Laurent Pinchart escreveu:  
> > >>> Cropping on the WPF sink pad restricts the left and top coordinates to
> > >>> 0-255. The same result can be obtained by cropping on the RPF without
> > >>> any such restriction, this feature isn't useful. Disable it.
> > >>> 
> > >>> Signed-off-by: Laurent Pinchart
> > >>> <laurent.pinchart+renesas@ideasonboard.com>
> > >>> ---
> > >>> 
> > >>>  drivers/media/platform/vsp1/vsp1_rwpf.c | 37 ++++++++++++------------
> > >>>  drivers/media/platform/vsp1/vsp1_wpf.c  | 18 +++++++---------
> > >>>  2 files changed, 26 insertions(+), 29 deletions(-)
> > >>> 
> > >>> diff --git a/drivers/media/platform/vsp1/vsp1_rwpf.c
> > >>> b/drivers/media/platform/vsp1/vsp1_rwpf.c index
> > >>> 8cb87e96b78b..a3ace8df7f4d 100644
> > >>> --- a/drivers/media/platform/vsp1/vsp1_rwpf.c
> > >>> +++ b/drivers/media/platform/vsp1/vsp1_rwpf.c  
> 
> [snip]
> 
> > >>> @@ -129,8 +132,10 @@ static int vsp1_rwpf_get_selection(struct
> > >>> v4l2_subdev *subdev,
> > >>>  	struct v4l2_mbus_framefmt *format;
> > >>>  	int ret = 0;
> > >>> 
> > >>> -	/* Cropping is implemented on the sink pad. */
> > >>> -	if (sel->pad != RWPF_PAD_SINK)
> > >>> +	/* Cropping is only supported on the RPF and is implemented on
> > >>> the sink
> > >>> +	 * pad.
> > >>> +	 */  
> > >> 
> > >> Please read CodingStyle and run checkpatch before sending stuff
> > >> upstream.
> > >> 
> > >> This violates the CodingStyle: it should be, instead:
> > >> 	/*
> > >> 	 * foo
> > >> 	 * bar
> > >> 	 */  
> > > 
> > > But it's consistent with the coding style of this driver. I'm OK fixing
> > > it, but it should be done globally in that case.  
> > 
> > There are inconsistencies inside the driver too on multi-line
> > comments even without fixing the ones introduced on this series,
> > as, on several places, multi-line comments are correct:
> > 
> > drivers/media/platform/vsp1/vsp1_bru.c:/*
> > drivers/media/platform/vsp1/vsp1_bru.c- * The BRU can't perform format
> > conversion, all sink and source formats must be
> > drivers/media/platform/vsp1/vsp1_bru.c- * identical. We pick the format on
> > the first sink pad (pad 0) and propagate it
> > drivers/media/platform/vsp1/vsp1_bru.c- * to all other pads.
> > drivers/media/platform/vsp1/vsp1_bru.c- */
> > 
> > drivers/media/platform/vsp1/vsp1_dl.c:/*
> > drivers/media/platform/vsp1/vsp1_dl.c- * Initialize a display list body
> > object and allocate DMA memory for the body
> > drivers/media/platform/vsp1/vsp1_dl.c- * data. The display list body object
> > is expected to have been initialized to
> > drivers/media/platform/vsp1/vsp1_dl.c- * 0 when allocated.
> > drivers/media/platform/vsp1/vsp1_dl.c- */
> > 
> > ...
> > 
> > I'll address the ones only the CodingStyle violation introduced by this
> > series. I'll leave for the vsp1 maintainers/developers.  
> 
> OK, I'll address that.
> 
> > Btw, there are several kernel-doc tags that use just:
> > 	/*
> > 	 ...
> > 	 */
> > 
> > instead of:
> > 
> > 	/**
> > 	 ...
> > 	 */
> > 
> > I suggest you to add the files/headers with kernel-doc markups on
> > a Documentation/media/v4l-drivers/vsp1.rst file, to be created.
> > 
> > This way, you can validate that such documentation is correct,
> > and produce an auto-generated documentation for this driver.  
> 
> I've thought about it, but I don't think those comments should become part of 
> the kernel documentation. They're really about driver internals, and meant for 
> the driver developers. In particular only a subset of the driver is documented 
> that way, when I've considered that the code or structures were complex enough 
> to need proper documentation. A generated doc would then be quite incomplete 
> and not very useful, the comments are meant to be read while working on the 
> code.

The v4l-drivers book is meant to have driver internals documentation,
and not the subsystem kAPI or uAPI.

I don't see any problems if you want to document just the more complex
functions/structs over the v4l-drivers/ book. Yet, as you already took
the time to write documentation for those functions, providing that the
kernel-doc markups are ok, a v4l-drivers/vsp1.rst file for it could be as
simple as (untested):


VSP1 driver
^^^^^^^^^^^

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_dl.c

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_drm.c

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_drm.h

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_entity.c

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_entity.h

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_pipe.c

.. kernel-doc:: drivers/media/platform/vsp1/vsp1_video.c

PS.: Eventually, you may need an extra attribute for the files with
EXPORT_SYMBOL*, in order to associate a *.c file with the
corresponding *.h file.