Re: [PATCH v4 03/13] media: pci: cx18-av-vbi: Replace open-coded parity calculation with parity_odd()

Kuan-Wei Chiu
2025-05-15T09:20:33Z

On Wed, Apr 09, 2025 at 08:43:09PM +0200, Arend van Spriel wrote:
> On 4/9/2025 5:43 PM, Kuan-Wei Chiu wrote:
> > Refactor parity calculations to use the standard parity_odd() helper.
> > This change eliminates redundant implementations.
> >
> > Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
> > Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
> > Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
> > ---
> > drivers/media/pci/cx18/cx18-av-vbi.c | 12 ++----------
> > 1 file changed, 2 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/media/pci/cx18/cx18-av-vbi.c b/drivers/media/pci/cx18/cx18-av-vbi.c
> > index 65281d40c681..15b515b95956 100644
> > --- a/drivers/media/pci/cx18/cx18-av-vbi.c
> > +++ b/drivers/media/pci/cx18/cx18-av-vbi.c
>
> [...]
>
> > @@ -278,7 +270,7 @@ int cx18_av_decode_vbi_line(struct v4l2_subdev *sd,
> > break;
> > case 6:
> > sdid = V4L2_SLICED_CAPTION_525;
> > - err = !odd_parity(p[0]) || !odd_parity(p[1]);
> > + err = !parity_odd(p[0]) || !parity_odd(p[1]);
>
> No need to call parity_odd() twice here. Instead you could do:
>
> err = !parity_odd(p[0] ^ p[1]);
>
> This is orthogonal to the change to parity_odd() though. More specific to
> the new parity_odd() you can now do following as parity_odd() argument is
> u64:
>
> err = !parity_odd(*(u16 *)p);
>
>
Thanks for the feedback!
Would you prefer this change to be part of the parity() conversion
patch, or in a separate one?

Regards,
Kuan-Wei