[PATCH] drm: Fix docbook warnings in hdr metadata helper structures

[Daniel Vetter]

On Wed, May 29, 2019 at 4:16 PM Uma Shankar <uma.shankar at intel.com> wrote:
>
> Fixes the following warnings:
> ./include/drm/drm_mode_config.h:841: warning: Incorrect use of
> kernel-doc format:          * hdr_output_metadata_property: Connector
> property containing hdr
> ./include/drm/drm_mode_config.h:918: warning: Function parameter or member 'hdr_output_metadata_property' not described in 'drm_mode_config'
> ./include/drm/drm_connector.h:1251: warning: Function parameter or member 'hdr_output_metadata' not described in 'drm_connector'
> ./include/drm/drm_connector.h:1251: warning: Function parameter or member 'hdr_sink_metadata' not described in 'drm_connector'
>
> Also adds some property documentation for HDR Metadata Connector
> Property in connector property create function.
>
> Cc: Shashank Sharma <shashank.sharma at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Maxime Ripard <maxime.ripard at bootlin.com>
> Cc: Sean Paul <sean at poorly.run>
> Cc: David Airlie <airlied at linux.ie>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
> Cc: "Ville Syrjälä" <ville.syrjala at linux.intel.com>
> Cc: Hans Verkuil <hansverk at cisco.com>
> Cc: dri-devel at lists.freedesktop.org
> Cc: linux-fbdev at vger.kernel.org
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 8 ++++++++
>  include/drm/drm_connector.h     | 3 ++-
>  include/drm/drm_mode_config.h   | 2 +-
>  include/linux/hdmi.h            | 1 +
>  4 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index c9ac8b9..702307c 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -1003,6 +1003,14 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
>   *     can also expose this property to external outputs, in which case they
>   *     must support "None", which should be the default (since external screens
>   *     have a built-in scaler).
> + *
> + * HDR_OUTPUT_METADATA:
> + *     Connector property to enable userspace to send HDR Metadata to driver.
> + *     This metadata is based on the composition and blending policies decided
> + *     by user, taking into account the hardware and sink capabilties.
> + *     The driver gets this metadata and creates a Dynamic Range and Mastering
> + *     Infoframe (DRM) which is then sent to sink. This notifies the sink of
> + *     the upcoming frame's Color Encoding and Luminance parameters.
>   */

Assuming I'm applying this correctly your adding this to the "lcd
panel properties" section. That doesn't make sense to me. I think we
already have a section for hdmi properties somewhere, would fit better
there.

This should also contain a bit more about how this is supposed to
work, how it's set up from a driver pov (sprinkle links all over it)
and how userspace it supposed to use it.

I think since this is a using a rather complicated struct I think we
need to fully document that structure too. Atm uapi/drm_mode.h isn't
pulled into anywhere, so we need to fix that (a new chapter titled
"Userspace API Structures" in drm-uapi.rst would be good, cross-links
will work).

>
>  int drm_connector_create_standard_properties(struct drm_device *dev)
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index f8f4003..f226ef0 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1244,8 +1244,9 @@ struct drm_connector {
>          */
>         struct llist_node free_node;
>
> -       /* HDR metdata */
> +       /** @hdr_output_metadata: HDR Metadata to be sent to sink */
>         struct hdr_output_metadata hdr_output_metadata;

Uh, is this even used? It would be a bug if so, since the state
userspace can set must be stored in drm_connector_state, not in
drm_connector. Only read-only stuff can be in there.

Please don't just blindly type docs, try to make sure that what you're
documenting actually makes sense. Also, should have been a clear sign
that you've forgotten to document one of the properties in the
enumeration above.
-Daniel

> +       /** @hdr_sink_metadata: HDR Metadata Information read from sink */
>         struct hdr_sink_metadata hdr_sink_metadata;
>  };
>
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index 4f88cc9..0b180e0 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -837,7 +837,7 @@ struct drm_mode_config {
>         struct drm_property *writeback_out_fence_ptr_property;
>
>         /**
> -        * hdr_output_metadata_property: Connector property containing hdr
> +        * @hdr_output_metadata_property: Connector property containing hdr
>          * metatda. This will be provided by userspace compositors based
>          * on HDR content
>          */
> diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
> index ee55ba5..ea5858e 100644
> --- a/include/linux/hdmi.h
> +++ b/include/linux/hdmi.h
> @@ -398,6 +398,7 @@ ssize_t hdmi_vendor_infoframe_pack_only(const struct hdmi_vendor_infoframe *fram
>   * @spd: spd infoframe
>   * @vendor: union of all vendor infoframes
>   * @audio: audio infoframe
> + * @drm: DRM infoframe
>   *
>   * This is used by the generic pack function. This works since all infoframes
>   * have the same header which also indicates which type of infoframe should be
> --
> 1.9.1
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch