On Tue, Oct 11, 2022 at 04:49:42PM +0300, Jani Nikula wrote:
> We've lacked a function for immutable validity check on drm_edid. Add
> one.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 30 ++++++++++++++++++++++++++++++
> include/drm/drm_edid.h | 1 +
> 2 files changed, 31 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 616c1cdc7507..c3cf942186b7 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2040,6 +2040,36 @@ bool drm_edid_is_valid(struct edid *edid)
> }
> EXPORT_SYMBOL(drm_edid_is_valid);
>
> +/**
> + * drm_edid_valid - sanity check EDID data
> + * @drm_edid: EDID data
> + *
> + * Sanity check an EDID. Cross check block count against allocated size and
> + * checksum the blocks.
> + *
> + * Return: True if the EDID data is valid, false otherwise.
> + */
> +bool drm_edid_valid(const struct drm_edid *drm_edid)
> +{
> + int i;
> +
> + if (!drm_edid)
> + return false;
> +
> + if (edid_size_by_blocks(__drm_edid_block_count(drm_edid)) != drm_edid->size)
> + return false;
I Was consfued about the HF-EEODB crap for a bit but
__drm_edid_block_count() does include that.
So looks sane
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> +
> + for (i = 0; i < drm_edid_block_count(drm_edid); i++) {
> + const void *block = drm_edid_block_data(drm_edid, i);
> +
> + if (!edid_block_valid(block, i == 0))
> + return false;
> + }
> +
> + return true;
> +}
> +EXPORT_SYMBOL(drm_edid_valid);
> +
> static struct edid *edid_filter_invalid_blocks(struct edid *edid,
> size_t *alloc_size)
> {
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index 05380681a4fb..a2e25e7e6ee5 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -606,6 +606,7 @@ drm_display_mode_from_cea_vic(struct drm_device *dev,
> const struct drm_edid *drm_edid_alloc(const void *edid, size_t size);
> const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid);
> void drm_edid_free(const struct drm_edid *drm_edid);
> +bool drm_edid_valid(const struct drm_edid *drm_edid);
> const struct edid *drm_edid_raw(const struct drm_edid *drm_edid);
> const struct drm_edid *drm_edid_read(struct drm_connector *connector);
> const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector,
> --
> 2.34.1
--
Ville Syrjälä
Intel
