Add a helper to compute vblank time needed for transmitting specific
DisplayPort SDPs like PPS, GAMUT_METADATA, and VSC_EXT. Latency is
based on line count per packet type and current line time.

This will be used to ensure adequate guardband when features like DSC/HDR
are enabled.

Bspec: 70151
Signed-off-by: Ankit Nautiyal <[email protected]>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 33 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dp.h |  1 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c 
b/drivers/gpu/drm/i915/display/intel_dp.c
index e481ff4c4959..54d31d02ba50 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6988,3 +6988,36 @@ void intel_dp_compute_config_late(struct intel_encoder 
*encoder,
 
        intel_psr_compute_config_late(intel_dp, crtc_state);
 }
+
+static
+int intel_dp_get_sdp_latency(u32 type)
+{
+       switch (type) {
+       case DP_SDP_VSC_EXT_VESA:
+       case DP_SDP_VSC_EXT_CEA:
+               return 10;
+       case HDMI_PACKET_TYPE_GAMUT_METADATA:
+               return 8;
+       case DP_SDP_PPS:
+               return 6;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+int intel_dp_compute_sdp_latency(const struct intel_crtc_state *crtc_state)
+{
+       int sdp_latency = 0;
+
+       if (crtc_state->infoframes.enable &
+           intel_hdmi_infoframe_enable(HDMI_PACKET_TYPE_GAMUT_METADATA))
+               sdp_latency = max(sdp_latency,
+                                 
intel_dp_get_sdp_latency(HDMI_PACKET_TYPE_GAMUT_METADATA));
+
+       if (crtc_state->dsc.compression_enable)
+               sdp_latency = max(sdp_latency, 
intel_dp_get_sdp_latency(DP_SDP_PPS));
+
+       return sdp_latency;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h 
b/drivers/gpu/drm/i915/display/intel_dp.h
index 0d9573ca44cb..27089cef86d8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -221,5 +221,6 @@ bool intel_dp_in_hdr_mode(const struct drm_connector_state 
*conn_state);
 void intel_dp_compute_config_late(struct intel_encoder *encoder,
                                  struct intel_crtc_state *crtc_state,
                                  struct drm_connector_state *conn_state);
+int intel_dp_compute_sdp_latency(const struct intel_crtc_state *crtc_state);
 
 #endif /* __INTEL_DP_H__ */
-- 
2.45.2

Reply via email to