From 26ff1c38fc29ec5eb51c84cfeda1bc3e27de3c13 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Mon, 27 May 2024 15:58:04 +0200 Subject: [PATCH 0737/1625] drm/connector: hdmi: Compute bpc and format automatically MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Now that we have all the infrastructure needed, we can add some code that will, for a given connector state and mode, compute the best output format and bpc. The algorithm is equivalent to the one already found in i915 and vc4. Cc: Ville Syrjälä Reviewed-by: Dmitry Baryshkov Link: https://patchwork.freedesktop.org/patch/msgid/20240527-kms-hdmi-connector-state-v15-15-c5af16c3aae2@kernel.org Signed-off-by: Maxime Ripard --- .../gpu/drm/display/drm_hdmi_state_helper.c | 217 +++++++++++++++++- 1 file changed, 214 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index 063421835dba..1623b96cd97c 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -2,6 +2,8 @@ #include #include +#include +#include #include #include @@ -48,6 +50,126 @@ connector_state_get_mode(const struct drm_connector_state *conn_state) return &crtc_state->mode; } +static bool +sink_supports_format_bpc(const struct drm_connector *connector, + const struct drm_display_info *info, + const struct drm_display_mode *mode, + unsigned int format, unsigned int bpc) +{ + struct drm_device *dev = connector->dev; + u8 vic = drm_match_cea_mode(mode); + + /* + * CTA-861-F, section 5.4 - Color Coding & Quantization states + * that the bpc must be 8, 10, 12 or 16 except for the default + * 640x480 VIC1 where the value must be 8. + * + * The definition of default here is ambiguous but the spec + * refers to VIC1 being the default timing in several occasions + * so our understanding is that for the default timing (ie, + * VIC1), the bpc must be 8. + */ + if (vic == 1 && bpc != 8) { + drm_dbg_kms(dev, "VIC1 requires a bpc of 8, got %u\n", bpc); + return false; + } + + if (!info->is_hdmi && + (format != HDMI_COLORSPACE_RGB || bpc != 8)) { + drm_dbg_kms(dev, "DVI Monitors require an RGB output at 8 bpc\n"); + return false; + } + + if (!(connector->hdmi.supported_formats & BIT(format))) { + drm_dbg_kms(dev, "%s format unsupported by the connector.\n", + drm_hdmi_connector_get_output_format_name(format)); + return false; + } + + switch (format) { + case HDMI_COLORSPACE_RGB: + drm_dbg_kms(dev, "RGB Format, checking the constraints.\n"); + + /* + * In some cases, like when the EDID readout fails, or + * is not an HDMI compliant EDID for some reason, the + * color_formats field will be blank and not report any + * format supported. In such a case, assume that RGB is + * supported so we can keep things going and light up + * the display. + */ + if (!(info->color_formats & DRM_COLOR_FORMAT_RGB444)) + drm_warn(dev, "HDMI Sink doesn't support RGB, something's wrong.\n"); + + if (bpc == 10 && !(info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30)) { + drm_dbg_kms(dev, "10 BPC but sink doesn't support Deep Color 30.\n"); + return false; + } + + if (bpc == 12 && !(info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_36)) { + drm_dbg_kms(dev, "12 BPC but sink doesn't support Deep Color 36.\n"); + return false; + } + + drm_dbg_kms(dev, "RGB format supported in that configuration.\n"); + + return true; + + case HDMI_COLORSPACE_YUV420: + /* TODO: YUV420 is unsupported at the moment. */ + drm_dbg_kms(dev, "YUV420 format isn't supported yet.\n"); + return false; + + case HDMI_COLORSPACE_YUV422: + drm_dbg_kms(dev, "YUV422 format, checking the constraints.\n"); + + if (!(info->color_formats & DRM_COLOR_FORMAT_YCBCR422)) { + drm_dbg_kms(dev, "Sink doesn't support YUV422.\n"); + return false; + } + + if (bpc > 12) { + drm_dbg_kms(dev, "YUV422 only supports 12 bpc or lower.\n"); + return false; + } + + /* + * HDMI Spec 1.3 - Section 6.5 Pixel Encodings and Color Depth + * states that Deep Color is not relevant for YUV422 so we + * don't need to check the Deep Color bits in the EDIDs here. + */ + + drm_dbg_kms(dev, "YUV422 format supported in that configuration.\n"); + + return true; + + case HDMI_COLORSPACE_YUV444: + drm_dbg_kms(dev, "YUV444 format, checking the constraints.\n"); + + if (!(info->color_formats & DRM_COLOR_FORMAT_YCBCR444)) { + drm_dbg_kms(dev, "Sink doesn't support YUV444.\n"); + return false; + } + + if (bpc == 10 && !(info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_30)) { + drm_dbg_kms(dev, "10 BPC but sink doesn't support Deep Color 30.\n"); + return false; + } + + if (bpc == 12 && !(info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_36)) { + drm_dbg_kms(dev, "12 BPC but sink doesn't support Deep Color 36.\n"); + return false; + } + + drm_dbg_kms(dev, "YUV444 format supported in that configuration.\n"); + + return true; + } + + drm_dbg_kms(dev, "Unsupported pixel format.\n"); + return false; +} + static enum drm_mode_status hdmi_clock_valid(const struct drm_connector *connector, const struct drm_display_mode *mode, @@ -92,6 +214,97 @@ hdmi_compute_clock(const struct drm_connector *connector, return 0; } +static bool +hdmi_try_format_bpc(const struct drm_connector *connector, + struct drm_connector_state *conn_state, + const struct drm_display_mode *mode, + unsigned int bpc, enum hdmi_colorspace fmt) +{ + const struct drm_display_info *info = &connector->display_info; + struct drm_device *dev = connector->dev; + int ret; + + drm_dbg_kms(dev, "Trying %s output format\n", + drm_hdmi_connector_get_output_format_name(fmt)); + + if (!sink_supports_format_bpc(connector, info, mode, fmt, bpc)) { + drm_dbg_kms(dev, "%s output format not supported with %u bpc\n", + drm_hdmi_connector_get_output_format_name(fmt), + bpc); + return false; + } + + ret = hdmi_compute_clock(connector, conn_state, mode, bpc, fmt); + if (ret) { + drm_dbg_kms(dev, "Couldn't compute clock for %s output format and %u bpc\n", + drm_hdmi_connector_get_output_format_name(fmt), + bpc); + return false; + } + + drm_dbg_kms(dev, "%s output format supported with %u (TMDS char rate: %llu Hz)\n", + drm_hdmi_connector_get_output_format_name(fmt), + bpc, conn_state->hdmi.tmds_char_rate); + + return true; +} + +static int +hdmi_compute_format(const struct drm_connector *connector, + struct drm_connector_state *conn_state, + const struct drm_display_mode *mode, + unsigned int bpc) +{ + struct drm_device *dev = connector->dev; + + /* + * TODO: Add support for YCbCr420 output for HDMI 2.0 capable + * devices, for modes that only support YCbCr420. + */ + if (hdmi_try_format_bpc(connector, conn_state, mode, bpc, HDMI_COLORSPACE_RGB)) { + conn_state->hdmi.output_format = HDMI_COLORSPACE_RGB; + return 0; + } + + drm_dbg_kms(dev, "Failed. No Format Supported for that bpc count.\n"); + + return -EINVAL; +} + +static int +hdmi_compute_config(const struct drm_connector *connector, + struct drm_connector_state *conn_state, + const struct drm_display_mode *mode) +{ + struct drm_device *dev = connector->dev; + unsigned int max_bpc = clamp_t(unsigned int, + conn_state->max_bpc, + 8, connector->max_bpc); + unsigned int bpc; + int ret; + + for (bpc = max_bpc; bpc >= 8; bpc -= 2) { + drm_dbg_kms(dev, "Trying with a %d bpc output\n", bpc); + + ret = hdmi_compute_format(connector, conn_state, mode, bpc); + if (ret) + continue; + + conn_state->hdmi.output_bpc = bpc; + + drm_dbg_kms(dev, + "Mode %ux%u @ %uHz: Found configuration: bpc: %u, fmt: %s, clock: %llu\n", + mode->hdisplay, mode->vdisplay, drm_mode_vrefresh(mode), + conn_state->hdmi.output_bpc, + drm_hdmi_connector_get_output_format_name(conn_state->hdmi.output_format), + conn_state->hdmi.tmds_char_rate); + + return 0; + } + + return -EINVAL; +} + /** * drm_atomic_helper_connector_hdmi_check() - Helper to check HDMI connector atomic state * @connector: DRM Connector @@ -115,9 +328,7 @@ int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector, connector_state_get_mode(new_conn_state); int ret; - ret = hdmi_compute_clock(connector, new_conn_state, mode, - new_conn_state->hdmi.output_bpc, - new_conn_state->hdmi.output_format); + ret = hdmi_compute_config(connector, new_conn_state, mode); if (ret) return ret; -- 2.52.0