Re: [PATCH 13/13] drm/msm/dp: Add static HDR metadata support for DP and eDP

[Dmitry Baryshkov]

On Wed, Sep 30, 2026 at 08:41:57PM +0800, Xilin Wu wrote:
> Expose HDR_OUTPUT_METADATA and validate and pack it during atomic check.
> Program Generic2 from the checked bridge state on every stream enable.
> Reuse the DRM metadata conversion and infoframe packing helpers, omit
> the HDMI checksum when constructing the DP SDP, and zero reserved bytes.
> 
> Require 10 bpc for HDR transfer functions and reject insufficient
> bandwidth after link training instead of silently reducing color depth.
> Revalidate sink HDR capabilities after powering up an eDP panel, using
> the stream enable failure path if the requested output is unsupported.
> 
> Force a modeset for metadata changes and include metadata enable and
> disable in peripheral flush requests. Keep HDR streams out of PSR and
> clear Generic2 enable state when disabling the stream. Preserve the
> software metadata across teardown so that every stream rebuild restores
> the checked packets.
> 
> Give checked HDR modesets precedence over SDR video-pattern tests. Reject
> new test requests with NAK while HDR is configured and return -EBUSY from
> the debugfs test control. Clear the test override under plugged_lock when
> applying HDR so that a request arriving after atomic check cannot replace
> the checked output depth. Keep pending test colorimetry from overriding
> HDR signalling. Atomic checks leave the running test state untouched.
> 
> Assisted-by: LLM
> Signed-off-by: Xilin Wu <sophon@xxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/Kconfig         |  1 +
>  drivers/gpu/drm/msm/dp/dp_ctrl.c    |  9 ++++--
>  drivers/gpu/drm/msm/dp/dp_display.c | 39 +++++++++++++++++++++---
>  drivers/gpu/drm/msm/dp/dp_drm.c     |  4 ++-
>  drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
>  drivers/gpu/drm/msm/dp/dp_panel.c   | 33 ++++++++++++++++++++
>  drivers/gpu/drm/msm/dp/dp_panel.h   |  3 ++
>  drivers/gpu/drm/msm/dp/dp_utils.c   | 61 ++++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/msm/dp/dp_utils.h   |  5 ++-
>  9 files changed, 145 insertions(+), 12 deletions(-)
> 
> @@ -717,17 +727,25 @@ int msm_dp_display_atomic_check(struct msm_dp *msm_dp_display,
>  
>  	guard(mutex)(&dp->plugged_lock);
>  
> +	ret = msm_dp_utils_pack_hdr_sdp(conn_state, &state->hdr_sdp);
> +	if (ret)
> +		return ret;
> +
> +	state->hdr_enabled = !!conn_state->hdr_output_metadata;

This should be done in atomic_check. Also please make sure that we don't
copy data from the state to the long-term structures. I'd rather pass
state pointer around.

>  	bpp = msm_dp_utils_select_bpp(info->bpc, conn_state->max_requested_bpc,
>  				      clock, dp->panel->link_caps_valid ?
>  				      dp->panel->link_info.rate : 0,
> -				      dp->panel->link_info.num_lanes);
> +				      dp->panel->link_info.num_lanes,
> +				      state->hdr_enabled && state->hdr_sdp.db[2] !=
> +				      HDMI_EOTF_TRADITIONAL_GAMMA_SDR);
>  	if (bpp < 0)
>  		return bpp;
>  
>  	state->bpp = bpp;
>  	state->colorspace = conn_state->colorspace;
>  	state->vsc_enabled = drm_mode_is_420_only(info, mode) ||
> -			     state->colorspace != DRM_MODE_COLORIMETRY_DEFAULT;
> +			     state->colorspace != DRM_MODE_COLORIMETRY_DEFAULT ||
> +			     state->hdr_enabled;
>  	if (!state->vsc_enabled)
>  		return 0;
>  

-- 
With best wishes
Dmitry