[PATCH 01/12] drm/i915/dp: Refactor FEC support check in intel_dp_supports_dsc

[Ankit Nautiyal]

Forward Error Correction is required for DP if we are using DSC but
is optional for eDP.

Currently the helper intel_dp_supports_dsc checks if fec_enable is set for
DP or not. The helper is called after fec_enable is set in crtc_state.

Instead of this a better approach would be to:
first, call intel_dp_supports_dsc to check for DSC support
(along with FEC requirement for DP) and then set fec_enable for DP
(if not already set) in crtc_state.

To achieve this, remove the check for fec_enable in the helper and instead
check for FEC support for DP. With this change the helper
intel_dp_supports_dsc can be called earlier and return early if DSC is
not supported. The structure intel_dp is added to the helper to get the
FEC support for DP.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c     | 8 +++++---
 drivers/gpu/drm/i915/display/intel_dp.h     | 3 ++-
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 5 +++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 053a9a4182e7..db9ddbcdd159 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1632,13 +1632,15 @@ bool intel_dp_supports_fec(struct intel_dp *intel_dp,
 		drm_dp_sink_supports_fec(connector->dp.fec_capability);
 }
 
-bool intel_dp_supports_dsc(const struct intel_connector *connector,
+bool intel_dp_supports_dsc(struct intel_dp *intel_dp,
+			   const struct intel_connector *connector,
 			   const struct intel_crtc_state *crtc_state)
 {
 	if (!intel_dp_has_dsc(connector))
 		return false;
 
-	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP) && !crtc_state->fec_enable)
+	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP) &&
+	    !intel_dp_supports_fec(intel_dp, connector, crtc_state))
 		return false;
 
 	return intel_dsc_source_support(crtc_state);
@@ -2376,7 +2378,7 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 		 intel_dp_supports_fec(intel_dp, connector, pipe_config) &&
 		 !intel_dp_is_uhbr(pipe_config));
 
-	if (!intel_dp_supports_dsc(connector, pipe_config))
+	if (!intel_dp_supports_dsc(intel_dp, connector, pipe_config))
 		return -EINVAL;
 
 	if (!intel_dp_dsc_supports_format(connector, pipe_config->output_format))
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 48f10876be65..4ae54e9718ce 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -170,7 +170,8 @@ bool intel_dp_supports_fec(struct intel_dp *intel_dp,
 			   const struct intel_connector *connector,
 			   const struct intel_crtc_state *pipe_config);
 
-bool intel_dp_supports_dsc(const struct intel_connector *connector,
+bool intel_dp_supports_dsc(struct intel_dp *intel_dp,
+			   const struct intel_connector *connector,
 			   const struct intel_crtc_state *crtc_state);
 
 u32 intel_dp_dsc_nearest_valid_bpp(struct drm_i915_private *i915, u32 bpp, u32 pipe_bpp);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index f058360a2641..0662736849ac 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -498,12 +498,13 @@ adjust_limits_for_dsc_hblank_expansion_quirk(const struct intel_connector *conne
 	struct intel_display *display = to_intel_display(connector);
 	const struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	int min_bpp_x16 = limits->link.min_bpp_x16;
+	struct intel_dp *intel_dp = connector->mst_port;
 
 	if (!hblank_expansion_quirk_needs_dsc(connector, crtc_state, limits))
 		return true;
 
 	if (!dsc) {
-		if (intel_dp_supports_dsc(connector, crtc_state)) {
+		if (intel_dp_supports_dsc(intel_dp, connector, crtc_state)) {
 			drm_dbg_kms(display->drm,
 				    "[CRTC:%d:%s][CONNECTOR:%d:%s] DSC needed by hblank expansion quirk\n",
 				    crtc->base.base.id, crtc->base.name,
@@ -648,7 +649,7 @@ static int mst_stream_compute_config(struct intel_encoder *encoder,
 			    str_yes_no(ret), str_yes_no(joiner_needs_dsc),
 			    str_yes_no(intel_dp->force_dsc_en));
 
-		if (!intel_dp_supports_dsc(connector, pipe_config))
+		if (!intel_dp_supports_dsc(intel_dp, connector, pipe_config))
 			return -EINVAL;
 
 		if (!mst_stream_compute_config_limits(intel_dp, connector,
-- 
2.45.2