On Wed, Jun 08, 2022 at 10:50:32AM +0300, Jani Nikula wrote:
> Add a function to get the cea data block collection size.
>
> Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nik...@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
> ---
> drivers/gpu/drm/drm_edid.c | 24 +++++++++++++++++++++---
> 1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index c57f6333ea7d..002816509fc8 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -4482,6 +4482,20 @@ __cea_db_iter_current_block(const struct cea_db_iter
> *iter)
> return NULL;
> }
>
> +/*
> + * References:
> + * - CTA-861-H section 7.3.3 CTA Extension Version 3
> + */
> +static int cea_db_collection_size(const u8 *cta)
> +{
> + u8 d = cta[2];
> +
> + if (d < 4 || d > 127)
> + return 0;
> +
> + return d - 4;
> +}
> +
> /*
> * References:
> * - VESA E-EDID v1.4
> @@ -4492,15 +4506,19 @@ static const void *__cea_db_iter_edid_next(struct
> cea_db_iter *iter)
> const u8 *ext;
>
> drm_edid_iter_for_each(ext, &iter->edid_iter) {
> + int size;
> +
> /* Only support CTA Extension revision 3+ */
> if (ext[0] != CEA_EXT || cea_revision(ext) < 3)
> continue;
>
> - iter->index = 4;
> - iter->end = ext[2];
> - if (iter->end < 4 || iter->end > 127)
> + size = cea_db_collection_size(ext);
> + if (!size)
> continue;
>
> + iter->index = 4;
> + iter->end = iter->index + size;
> +
> return ext;
> }
>
> --
> 2.30.2
--
Ville Syrjälä
Intel
