From fd8ce8da8be3a470242f5690d8759c2d0ccfeec3 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 30 Mar 2022 12:30:19 +0300
Subject: drm/i915/dp: make DSC usage logging actually useful
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Git-commit: 1dedcdd0336c356e7ac8eb9b3bc3fe3b4faeac8d
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Debug log when DSC is going to be used, and why, instead of
unconditionally logging the rarely used debug option setting, which
might not have any bearing on whether DSC is going to be used or not.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220330093019.4150386-1-jani.nikula@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index fb861c288c16..98ebfbcc3f8a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1483,6 +1483,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 		&pipe_config->hw.adjusted_mode;
 	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 	struct link_config_limits limits;
+	bool joiner_needs_dsc = false;
 	int ret;
 
 	limits.min_rate = intel_dp_common_rate(intel_dp, 0);
@@ -1518,19 +1519,23 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 				    adjusted_mode->crtc_clock))
 		pipe_config->bigjoiner_pipes = GENMASK(crtc->pipe + 1, crtc->pipe);
 
+	/*
+	 * Pipe joiner needs compression up to display 12 due to bandwidth
+	 * limitation. DG2 onwards pipe joiner can be enabled without
+	 * compression.
+	 */
+	joiner_needs_dsc = DISPLAY_VER(i915) < 13 && pipe_config->bigjoiner_pipes;
+
 	/*
 	 * Optimize for slow and wide for everything, because there are some
 	 * eDP 1.3 and 1.4 panels don't work well with fast and narrow.
 	 */
 	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
 
-	/*
-	 * Pipe joiner needs compression upto display12 due to BW limitation. DG2
-	 * onwards pipe joiner can be enabled without compression.
-	 */
-	drm_dbg_kms(&i915->drm, "Force DSC en = %d\n", intel_dp->force_dsc_en);
-	if (ret || intel_dp->force_dsc_en ||
-	    (DISPLAY_VER(i915) < 13 && pipe_config->bigjoiner_pipes)) {
+	if (ret || joiner_needs_dsc || intel_dp->force_dsc_en) {
+		drm_dbg_kms(&i915->drm, "Try DSC (fallback=%s, joiner=%s, force=%s)\n",
+			    str_yes_no(ret), str_yes_no(joiner_needs_dsc),
+			    str_yes_no(intel_dp->force_dsc_en));
 		ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
 						  conn_state, &limits);
 		if (ret < 0)
-- 
2.38.1