From 757ddb0f100c9589cb0aaed8f60bc8585037db22 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Tue, 22 Feb 2022 17:40:40 +0100
Subject: drm/vc4: hdmi: Take bpp into account for the scrambler
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Git-commit: f785dcfc596c378a19af01a6a337b8b67e5e4534
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

The current code only base its decision for whether the scrambler must be
enabled or not on the pixel clock of the mode, but doesn't take the bits
per color into account.

Let's leverage the new function to compute the clock rate in the
scrambler setup code.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220222164042.403112-6-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 16 ++++++++++++----
 drivers/gpu/drm/vc4/vc4_hdmi.h |  5 +++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index ca3fd4fb1c4f..a01b8386352e 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -100,9 +100,16 @@
 
 #define HDMI_14_MAX_TMDS_CLK   (340 * 1000 * 1000)
 
-static bool vc4_hdmi_mode_needs_scrambling(const struct drm_display_mode *mode)
+static unsigned long long
+vc4_hdmi_encoder_compute_mode_clock(const struct drm_display_mode *mode,
+				    unsigned int bpc);
+
+static bool vc4_hdmi_mode_needs_scrambling(const struct drm_display_mode *mode,
+					   unsigned int bpc)
 {
-	return (mode->clock * 1000) > HDMI_14_MAX_TMDS_CLK;
+	unsigned long long clock = vc4_hdmi_encoder_compute_mode_clock(mode, bpc);
+
+	return clock > HDMI_14_MAX_TMDS_CLK;
 }
 
 static bool vc4_hdmi_is_full_range_rgb(struct vc4_hdmi *vc4_hdmi,
@@ -267,7 +274,7 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)
 		struct drm_display_mode *mode;
 
 		list_for_each_entry(mode, &connector->probed_modes, head) {
-			if (vc4_hdmi_mode_needs_scrambling(mode)) {
+			if (vc4_hdmi_mode_needs_scrambling(mode, 8)) {
 				drm_warn_once(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
 				drm_warn_once(drm, "Please change your config.txt file to add hdmi_enable_4kp60.");
 			}
@@ -608,7 +615,7 @@ static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
 	if (!vc4_hdmi_supports_scrambling(encoder, mode))
 		return;
 
-	if (!vc4_hdmi_mode_needs_scrambling(mode))
+	if (!vc4_hdmi_mode_needs_scrambling(mode, vc4_hdmi->output_bpc))
 		return;
 
 	drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, true);
@@ -1237,6 +1244,7 @@ static void vc4_hdmi_encoder_atomic_mode_set(struct drm_encoder *encoder,
 	mutex_lock(&vc4_hdmi->mutex);
 	drm_mode_copy(&vc4_hdmi->saved_adjusted_mode,
 		      &crtc_state->adjusted_mode);
+	vc4_hdmi->output_bpc = conn_state->max_bpc;
 	mutex_unlock(&vc4_hdmi->mutex);
 }
 
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index 17e597af4a5f..d61fb060814a 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -220,6 +220,11 @@ struct vc4_hdmi {
 	 * the scrambler on? Protected by @mutex.
 	 */
 	bool scdc_enabled;
+
+	/**
+	 * @output_bpc: BPC currently being used. Protected by @mutex.
+	 */
+	unsigned int output_bpc;
 };
 
 static inline struct vc4_hdmi *
-- 
2.38.1