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 the same one than the one already found in i915 and
vc4.
Signed-off-by: Maxime Ripard <mrip...@kernel.org>
---
drivers/gpu/drm/drm_atomic_state_helper.c | 185 +++++++++++++++++++++++++++++-
1 file changed, 181 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c
b/drivers/gpu/drm/drm_atomic_state_helper.c
index 0dd1dad99cce..1420d9fdfa35 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -670,6 +670,96 @@ static bool hdmi_is_full_range(const struct drm_connector
*connector,
return drm_default_rgb_quant_range(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);
+
+ if (vic == 1 && bpc != 8) {
+ drm_dbg(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(dev, "DVI Monitors require an RGB output at 8 bpc\n");
+ return false;
+ }
+
+ if (!(connector->hdmi.supported_formats & BIT(format))) {
+ drm_dbg(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(dev, "RGB Format, checking the constraints.\n");
+
+ if (!(info->color_formats & DRM_COLOR_FORMAT_RGB444))
+ return false;
+
+ if (bpc == 10 && !(info->edid_hdmi_rgb444_dc_modes &
DRM_EDID_HDMI_DC_30)) {
+ drm_dbg(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(dev, "12 BPC but sink doesn't support Deep
Color 36.\n");
+ return false;
+ }
+
+ drm_dbg(dev, "RGB format supported in that configuration.\n");
+
+ return true;
+
+ case HDMI_COLORSPACE_YUV422:
+ drm_dbg(dev, "YUV422 format, checking the constraints.\n");
+
+ if (!(info->color_formats & DRM_COLOR_FORMAT_YCBCR422)) {
+ drm_dbg(dev, "Sink doesn't support YUV422.\n");
+ return false;
+ }
+
+ if (bpc != 12) {
+ drm_dbg(dev, "YUV422 only supports 12 bpc.\n");
+ return false;
+ }
+
+ drm_dbg(dev, "YUV422 format supported in that
configuration.\n");
+
+ return true;
+
+ case HDMI_COLORSPACE_YUV444:
+ drm_dbg(dev, "YUV444 format, checking the constraints.\n");
+
+ if (!(info->color_formats & DRM_COLOR_FORMAT_YCBCR444)) {
+ drm_dbg(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(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(dev, "12 BPC but sink doesn't support Deep
Color 36.\n");
+ return false;
+ }
+
+ drm_dbg(dev, "YUV444 format supported in that
configuration.\n");
+
+ return true;
+ }
+
+ return false;
+}
+
static enum drm_mode_status
hdmi_clock_valid(const struct drm_connector *connector,
const struct drm_display_mode *mode,
@@ -714,6 +804,95 @@ 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 *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(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(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, state, mode, bpc, fmt);
+ if (ret) {
+ drm_dbg(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(dev, "%s output format supported with %u (TMDS char rate: %llu
Hz)\n",
+ drm_hdmi_connector_get_output_format_name(fmt), bpc,
state->hdmi.tmds_char_rate);
+
+ return true;
+}
+
+static int
+hdmi_compute_format(const struct drm_connector *connector,
+ struct drm_connector_state *state,
+ const struct drm_display_mode *mode,
+ unsigned int bpc)
+{
+ struct drm_device *dev = connector->dev;
+
+ if (hdmi_try_format_bpc(connector, state, mode, bpc,
HDMI_COLORSPACE_RGB)) {
+ state->hdmi.output_format = HDMI_COLORSPACE_RGB;
+ return 0;
+ }
+
+ if (hdmi_try_format_bpc(connector, state, mode, bpc,
HDMI_COLORSPACE_YUV422)) {
+ state->hdmi.output_format = HDMI_COLORSPACE_YUV422;
+ return 0;
+ }
+
+ drm_dbg(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 *state,
+ const struct drm_display_mode *mode)
+{
+ struct drm_device *dev = connector->dev;
+ unsigned int max_bpc = clamp_t(unsigned int,
+ state->max_bpc,
+ 8, connector->max_bpc);
+ unsigned int bpc;
+ int ret;
+
+ for (bpc = max_bpc; bpc >= 8; bpc -= 2) {
+ drm_dbg(dev, "Trying with a %d bpc output\n", bpc);
+
+ ret = hdmi_compute_format(connector, state, mode, bpc);
+ if (ret)
+ continue;
+
+ state->hdmi.output_bpc = bpc;
+
+ drm_dbg(dev,
+ "Mode %ux%u @ %uHz: Found configuration: bpc: %u, fmt:
%s, clock: %llu\n",
+ mode->hdisplay, mode->vdisplay, drm_mode_vrefresh(mode),
+ state->hdmi.output_bpc,
+
drm_hdmi_connector_get_output_format_name(state->hdmi.output_format),
+ 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
@@ -739,10 +918,8 @@ int drm_atomic_helper_connector_hdmi_check(struct
drm_connector *connector,
new_state->hdmi.is_full_range = hdmi_is_full_range(connector,
new_state);
- ret = hdmi_compute_clock(connector, new_state, mode,
- new_state->hdmi.output_bpc,
- new_state->hdmi.output_format);
- if (!ret)
+ ret = hdmi_compute_config(connector, new_state, mode);
+ if (ret)
return ret;
if (old_state->hdmi.broadcast_rgb != new_state->hdmi.broadcast_rgb ||
--
2.41.0
