Re: [PATCH v1] media: i2c: alvium: Fix controls for WB/AWB

[Martin Hecht]

Hi Sakari,

thank you for the comments.

On 5/6/26 11:28, Sakari Ailus wrote:
> Hi Martin,
>
> Thanks for the patch.
>
> On Tue, May 05, 2026 at 04:25:10PM +0200, Martin Hecht wrote:
> > With that patch the controls for red-balance and blue-balance were created
> > only if the particular camera supports that. Otherwise the pointers on
> > the control variable are initialized with NULL to prevent side effects for
> > clustering with AWB control.
> >
> > Fixes: 0a7af872915e ("media: i2c: Add support for alvium camera")
> > Signed-off-by: Martin Hecht <mhecht73@xxxxxxxxx>
> > ---
> >   drivers/media/i2c/alvium-csi2.c | 37 ++++++++++++++++++++-------------
> >   1 file changed, 22 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/media/i2c/alvium-csi2.c b/drivers/media/i2c/alvium-csi2.c
> > index b62b45a4f2fc..4c6934e9e177 100644
> > --- a/drivers/media/i2c/alvium-csi2.c
> > +++ b/drivers/media/i2c/alvium-csi2.c
> > @@ -2108,26 +2108,33 @@ static int alvium_ctrl_init(struct alvium_dev *alvium)
> >   						  0, 0, &alvium->link_freq);
> >   	ctrls->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
>
> This is a problem. Can you move setting the flags after checking the
> handler's error status? The functions adding controls may fail and this is
> simply a missing error check.
>
> Can you submit a fix, with a Fixes: tag and this patch should be rebased on
> the fix, please?

I'm preparing a separate fix for that issue. It's the same situation 
also  for some other controls like pixel_rate and link_frequency but not 
only. Can I combine that into one patch for fix only that in 
alvium_ctrl_init?

> >   
> > +	if (alvium->avail_ft.whiteb) {
> > +		ctrls->blue_balance = v4l2_ctrl_new_std(hdl, ops,
> > +							V4L2_CID_BLUE_BALANCE,
> > +							alvium->min_bbalance,
> > +							alvium->max_bbalance,
> > +							alvium->inc_bbalance,
> > +							alvium->dft_bbalance);
> > +		ctrls->red_balance = v4l2_ctrl_new_std(hdl, ops,
> > +						       V4L2_CID_RED_BALANCE,
> > +						       alvium->min_rbalance,
> > +						       alvium->max_rbalance,
> > +						       alvium->inc_rbalance,
> > +						       alvium->dft_rbalance);
> > +	} else {
> > +		/* set to NULL for v4l2_ctrl_auto_cluster if not existing */
> > +		ctrls->blue_balance	= NULL;
> > +		ctrls->red_balance = NULL;
>
> Aren't the two NULL already before this?

You are right. It's zeroed before because __GFP_ZERO in devm_kzalloc. 
Will remove that redundant code.

> > +	}
> > +
> >   	/* Auto/manual white balance */
> >   	if (alvium->avail_ft.auto_whiteb) {
> >   		ctrls->auto_wb = v4l2_ctrl_new_std(hdl, ops,
> >   						   V4L2_CID_AUTO_WHITE_BALANCE,
> >   						   0, 1, 1, 1);
> > -		v4l2_ctrl_auto_cluster(3, &ctrls->auto_wb, 0, false);
> > -	}
> > -
> > -	ctrls->blue_balance = v4l2_ctrl_new_std(hdl, ops,
> > -						V4L2_CID_BLUE_BALANCE,
> > -						alvium->min_bbalance,
> > -						alvium->max_bbalance,
> > -						alvium->inc_bbalance,
> > -						alvium->dft_bbalance);
> > -	ctrls->red_balance = v4l2_ctrl_new_std(hdl, ops,
> > -					       V4L2_CID_RED_BALANCE,
> > -					       alvium->min_rbalance,
> > -					       alvium->max_rbalance,
> > -					       alvium->inc_rbalance,
> > -					       alvium->dft_rbalance);
> > +
> > +		v4l2_ctrl_auto_cluster(3, &ctrls->auto_wb, 0, true);
> > +	}
> >   
> >   	/* Auto/manual exposure */
> >   	if (alvium->avail_ft.auto_exp) {

BR Martin