[5/7] drm/i915/dp: Enable AUX based backlight for HDR
Sebastian Wick
sebastian.wick at redhat.com
Fri Apr 5 18:20:26 UTC 2024
On Thu, Apr 04, 2024 at 08:59:29AM +0530, Suraj Kandpal wrote:
> As of now whenerver HDR is switched on we use the PWM to change the
> backlight as opposed to AUX based backlight changes in terms of nits.
> This patch writes to the appropriate DPCD registers to enable aux
> based backlight using values in nits.
>
> --v2
> -Fix max_cll and max_fall assignment [Jani]
> -Fix the size sent in drm_dpcd_write [Jani]
>
> --v3
> -Content Luminance needs to be sent only for pre-ICL after that
> it is directly picked up from hdr metadata [Ville]
>
> --v4
> -Add checks for HDR TCON cap bits [Ville]
> -Check eotf of hdr_output_data and sets bits base of that value.
>
> --v5
> -Fix capability check bits.
> -Check colorspace before setting BT2020
>
> --v6
> -Use intel_dp_has_gamut_dip to check if we have capability
> to send sdp [Ville]
> -Seprate filling of all hdr tcon related bits into it's
> own function.
> -Check eotf data to make sure we are in HDR mode [Sebastian]
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
> .../drm/i915/display/intel_dp_aux_backlight.c | 105 ++++++++++++++++--
> 1 file changed, 94 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> index 2d50a4734823..7af876e2d210 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -40,11 +40,6 @@
> #include "intel_dp.h"
> #include "intel_dp_aux_backlight.h"
>
> -/* TODO:
> - * Implement HDR, right now we just implement the bare minimum to bring us back into SDR mode so we
> - * can make people's backlights work in the mean time
> - */
> -
> /*
> * DP AUX registers for Intel's proprietary HDR backlight interface. We define
> * them here since we'll likely be the only driver to ever use these.
> @@ -127,9 +122,6 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
> if (ret != sizeof(tcon_cap))
> return false;
>
> - if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP))
> - return false;
> -
> drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] Detected %s HDR backlight interface version %d\n",
> connector->base.base.id, connector->base.name,
> is_intel_tcon_cap(tcon_cap) ? "Intel" : "unsupported", tcon_cap[0]);
> @@ -137,6 +129,9 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
> if (!is_intel_tcon_cap(tcon_cap))
> return false;
>
> + if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP))
> + return false;
> +
> /*
> * If we don't have HDR static metadata there is no way to
> * runtime detect used range for nits based control. For now
> @@ -225,13 +220,27 @@ intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state,
> connector->base.base.id, connector->base.name);
> }
>
> +static bool
> +intel_dp_aux_in_hdr_mode(const struct drm_connector_state *conn_state)
> +{
> + struct hdr_output_metadata *hdr_metadata;
> +
> + if (!conn_state->hdr_output_metadata)
> + return false;
> +
> + hdr_metadata = conn_state->hdr_output_metadata->data;
> +
> + return hdr_metadata->hdmi_metadata_type1.eotf != HDMI_EOTF_TRADITIONAL_GAMMA_SDR;
This line worries me a bit. The TCON only supports PQ HDR mode so when
the metadata request HLG or traditional gamma HDR then only the
segmented backlight is enable in intel_dp_aux_fill_hdr_tcon_params but
it uses HDR backlight.
Did you test that this doesn't result in a black screen? Maybe change
this to `eotf == HDMI_EOTF_SMPTE_ST2084` instead?
> +}
> +
> static void
> intel_dp_aux_hdr_set_backlight(const struct drm_connector_state *conn_state, u32 level)
> {
> struct intel_connector *connector = to_intel_connector(conn_state->connector);
> struct intel_panel *panel = &connector->panel;
>
> - if (panel->backlight.edp.intel.sdr_uses_aux) {
> + if (intel_dp_aux_in_hdr_mode(conn_state) ||
> + panel->backlight.edp.intel.sdr_uses_aux) {
> intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
> } else {
> const u32 pwm_level = intel_backlight_level_to_pwm(connector, level);
> @@ -240,6 +249,70 @@ intel_dp_aux_hdr_set_backlight(const struct drm_connector_state *conn_state, u32
> }
> }
>
> +static void
> +intel_dp_aux_write_content_luminance(struct intel_connector *connector,
> + struct hdr_output_metadata *hdr_metadata)
> +{
> + struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
> + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> + int ret;
> + u8 buf[4];
> +
> + if (!intel_dp_has_gamut_metadata_dip(connector->encoder))
> + return;
I don't entirely understand intel_dp_has_gamut_metadata_dip, but I
assume it is true when the SDP HDR stuff can be send?
Either way, you only enable the HDR_OUTPUT_METADATA property if
intel_dp_has_gamut_metadata_dip returns true, so you will only ever have
intel_dp_aux_in_hdr_mode return true if the dip exists. So, this doesn't
do anything.
I think what you need is
* attach the HDR_OUTPUT_METADATA property if you can send the SDP thing
and the TCON supports the SDP override (>ICL) OR you can control HDR
via AUX (>=ICL).
* always set the content luminance via AUX
> +
> + buf[0] = hdr_metadata->hdmi_metadata_type1.max_cll & 0xFF;
> + buf[1] = (hdr_metadata->hdmi_metadata_type1.max_cll & 0xFF00) >> 8;
> + buf[2] = hdr_metadata->hdmi_metadata_type1.max_fall & 0xFF;
> + buf[3] = (hdr_metadata->hdmi_metadata_type1.max_fall & 0xFF00) >> 8;
> +
> + ret = drm_dp_dpcd_write(&intel_dp->aux,
> + INTEL_EDP_HDR_CONTENT_LUMINANCE,
> + buf, sizeof(buf));
> + if (ret < 0)
> + drm_dbg_kms(&i915->drm,
> + "Content Luminance DPCD reg write failed, err:-%d\n",
> + ret);
> +}
> +
> +static void
> +intel_dp_aux_fill_hdr_tcon_params(const struct drm_connector_state *conn_state, u8 *ctrl)
> +{
> + struct intel_connector *connector = to_intel_connector(conn_state->connector);
> + struct intel_panel *panel = &connector->panel;
> + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> + struct hdr_output_metadata *hdr_metadata = conn_state->hdr_output_metadata->data;
> +
> + /* According to spec segmented backlight needs to be set whenever panel is in
> + * HDR mode.
> + */
> + *ctrl |= INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_ENABLE;
> +
> + /* 2084 decode needs to set if eotf suggests so or in case of pre-ICL we disable
> + * tone mapping and set 2084 decode.
> + */
> + if (hdr_metadata->hdmi_metadata_type1.eotf ==
> + HDMI_EOTF_SMPTE_ST2084 || DISPLAY_VER(i915) < 11) {
> + *ctrl |= INTEL_EDP_HDR_TCON_2084_DECODE_ENABLE;
> + *ctrl &= ~INTEL_EDP_HDR_TCON_TONE_MAPPING_ENABLE;
> + } else {
> + drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] TCON: Cannot decode requested EOTF\n",
> + connector->base.base.id, connector->base.name);
> + }
> +
> + if (panel->backlight.edp.intel.supports_2020_gamut &&
> + (conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_RGB ||
> + conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_YCC ||
> + conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_CYCC))
> + *ctrl |= INTEL_EDP_HDR_TCON_2020_GAMUT_ENABLE;
> +
> + if (panel->backlight.edp.intel.supports_sdp_colorimetry &&
> + intel_dp_has_gamut_metadata_dip(connector->encoder))
> + *ctrl |= INTEL_EDP_HDR_TCON_SDP_OVERRIDE_AUX;
> + else
> + *ctrl &= ~INTEL_EDP_HDR_TCON_SDP_OVERRIDE_AUX;
> +}
> +
> static void
> intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
> const struct drm_connector_state *conn_state, u32 level)
> @@ -248,6 +321,7 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
> struct intel_panel *panel = &connector->panel;
> struct drm_i915_private *i915 = to_i915(connector->base.dev);
> struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
> + struct hdr_output_metadata *hdr_metadata;
> int ret;
> u8 old_ctrl, ctrl;
>
> @@ -261,8 +335,10 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
> }
>
> ctrl = old_ctrl;
> - if (panel->backlight.edp.intel.sdr_uses_aux) {
> + if (intel_dp_aux_in_hdr_mode(conn_state) ||
> + panel->backlight.edp.intel.sdr_uses_aux) {
> ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;
> +
> intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
> } else {
> u32 pwm_level = intel_backlight_level_to_pwm(connector, level);
> @@ -272,10 +348,18 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
> ctrl &= ~INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;
> }
>
> + if (intel_dp_aux_in_hdr_mode(conn_state))
> + intel_dp_aux_fill_hdr_tcon_params(conn_state, &ctrl);
> +
> if (ctrl != old_ctrl &&
> drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) != 1)
> drm_err(&i915->drm, "[CONNECTOR:%d:%s] Failed to configure DPCD brightness controls\n",
> connector->base.base.id, connector->base.name);
> +
> + if (intel_dp_aux_in_hdr_mode(conn_state)) {
> + hdr_metadata = conn_state->hdr_output_metadata->data;
> + intel_dp_aux_write_content_luminance(connector, hdr_metadata);
> + }
> }
>
> static void
> @@ -332,7 +416,6 @@ intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pi
> connector->base.base.id, connector->base.name,
> panel->backlight.min, panel->backlight.max);
>
> -
> panel->backlight.level = intel_dp_aux_hdr_get_backlight(connector, pipe);
> panel->backlight.enabled = panel->backlight.level != 0;
>
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