From: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Date: Fri, 17 Oct 2025 12:35:02 +0000 (+0530)
Subject: drm/i915/dp: Check if guardband can accommodate sdp latencies
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=69d640edc2630d903f25ab8ff8bf7d96d0776ce2;p=thirdparty%2Fkernel%2Flinux.git

drm/i915/dp: Check if guardband can accommodate sdp latencies

Check if guardband is sufficient for all DP SDP latencies.
If its not, fail .compute_config_late().

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20251017123504.2247954-4-ankit.k.nautiyal@intel.com
---

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9441ef6852005..b0aeb6c2de86c 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -93,6 +93,7 @@
 #include "intel_psr.h"
 #include "intel_quirks.h"
 #include "intel_tc.h"
+#include "intel_vblank.h"
 #include "intel_vdsc.h"
 #include "intel_vrr.h"
 
@@ -6992,14 +6993,35 @@ void intel_dp_mst_resume(struct intel_display *display)
 	}
 }
 
+static
+int intel_dp_sdp_compute_config_late(struct intel_crtc_state *crtc_state)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+	int guardband = intel_crtc_vblank_length(crtc_state);
+	int min_sdp_guardband = intel_dp_sdp_min_guardband(crtc_state, false);
+
+	if (guardband < min_sdp_guardband) {
+		drm_dbg_kms(display->drm, "guardband %d < min sdp guardband %d\n",
+			    guardband, min_sdp_guardband);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 int intel_dp_compute_config_late(struct intel_encoder *encoder,
 				 struct intel_crtc_state *crtc_state,
 				 struct drm_connector_state *conn_state)
 {
 	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+	int ret;
 
 	intel_psr_compute_config_late(intel_dp, crtc_state);
 
+	ret = intel_dp_sdp_compute_config_late(crtc_state);
+	if (ret)
+		return ret;
+
 	return 0;
 }