Re: [PATCH v3 18/29] media: bcm2835-unicam: Remove frame descriptor workaround

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Frank,

On Mon, Aug 24, 2026 at 05:10:13PM -0400, Frank Li wrote:
> On Mon, Aug 24, 2026 at 03:14:40PM +0300, Sakari Ailus wrote:
> > As the v4l2_subdev_get_frame_desc() either returns a frame descriptor or
> > returns an error, remove the workaround for drivers that didn't implement
> > the get_frame_desc() pad op. Also handle v4l2_subdev_get_frame_desc()
> > errors.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  .../media/platform/broadcom/bcm2835-unicam.c  | 26 +++++++++----------
> >  1 file changed, 12 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
> > index 2322d3df3915..ba613966c333 100644
> > --- a/drivers/media/platform/broadcom/bcm2835-unicam.c
> > +++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
> > @@ -918,8 +918,8 @@ static int unicam_get_image_vc_dt(struct unicam_device *unicam,
> >  	return -EINVAL;
> >  }
> >
> > -static void unicam_start_rx(struct unicam_device *unicam,
> > -			    struct v4l2_subdev_state *state)
> > +static int unicam_start_rx(struct unicam_device *unicam,
> > +			   struct v4l2_subdev_state *state)
> >  {
> >  	struct unicam_node *node = &unicam->node[UNICAM_IMAGE_NODE];
> >  	const struct unicam_format_info *fmtinfo;
> > @@ -933,7 +933,11 @@ static void unicam_start_rx(struct unicam_device *unicam,
> >  	fmtinfo = unicam_find_format_by_code(fmt->code,
> >  					     UNICAM_SD_PAD_SOURCE_IMAGE);
> >  	if (WARN_ON(!fmtinfo))
> > -		return;
> > +		return -EINVAL;
> > +
> > +	ret = unicam_get_image_vc_dt(unicam, state, &vc, &dt);
> > +	if (ret)
> > +		return ret;
> >
> >  	/*
> >  	 * Enable lane clocks. The register is structured as follows:
> > @@ -1090,16 +1094,6 @@ static void unicam_start_rx(struct unicam_device *unicam,
> >  	unicam_wr_dma_addr(node, node->cur_frm);
> >  	unicam_set_packing_config(unicam, fmtinfo);
> >
> > -	ret = unicam_get_image_vc_dt(unicam, state, &vc, &dt);
> > -	if (ret) {
> > -		/*
> > -		 * If the source doesn't support frame descriptors, default to
> > -		 * VC 0 and use the DT corresponding to the format.
> > -		 */
> > -		vc = 0;
> > -		dt = fmtinfo->csi_dt;
> > -	}
> > -
> 
> look likes vc=0, dt=0 change in patch 17 should be in this patch?

It seems like that, yes. The compilers aren't smart enough to figure out
they're not used when not set.

-- 
Sakari Ailus