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

Arend van Spriel
2025-04-09T18:43:28Z

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);

Regards,
Arend