950-0758-drm-vc4-kms-Improve-logging.patch

From 0fc2455e0b6cf188c529915de2627bdfb3e5ff01 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 4 Mar 2022 15:59:40 +0100
Subject: [PATCH] drm/vc4: kms: Improve logging

When debugging, finding out what muxing decisions were made and what the
actual core clock rate is is always useful, so let's add some more
messages.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_kms.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -447,6 +447,9 @@ static void vc4_atomic_commit_tail(struc
 
 		/* And drop the temporary request */
 		clk_request_done(core_req);
+
+		drm_dbg(dev, "Core clock actual rate: %lu Hz\n",
+			clk_get_rate(hvs->core_clk));
 	}
 }
 
@@ -827,9 +830,18 @@ static int vc4_pv_muxing_atomic_check(st
 		if (vc4->firmware_kms)
 			continue;
 
+		drm_dbg(dev, "%s: Trying to find a channel.\n", crtc->name);
+
 		/* Nothing to do here, let's skip it */
-		if (old_crtc_state->enable == new_crtc_state->enable)
+		if (old_crtc_state->enable == new_crtc_state->enable) {
+			if (new_crtc_state->enable)
+				drm_dbg(dev, "%s: Already enabled, reusing channel %d.\n",
+					crtc->name, new_vc4_crtc_state->assigned_channel);
+			else
+				drm_dbg(dev, "%s: Disabled, ignoring.\n", crtc->name);
+
 			continue;
+		}
 
 		/* Muxing will need to be modified, mark it as such */
 		new_vc4_crtc_state->update_muxing = true;
@@ -837,6 +849,10 @@ static int vc4_pv_muxing_atomic_check(st
 		/* If we're disabling our CRTC, we put back our channel */
 		if (!new_crtc_state->enable) {
 			channel = old_vc4_crtc_state->assigned_channel;
+
+			drm_dbg(dev, "%s: Disabling, Freeing channel %d\n",
+				crtc->name, channel);
+
 			hvs_new_state->fifo_state[channel].in_use = false;
 			new_vc4_crtc_state->assigned_channel = VC4_HVS_CHANNEL_DISABLED;
 			continue;
@@ -871,6 +887,8 @@ static int vc4_pv_muxing_atomic_check(st
 			return -EINVAL;
 
 		channel = ffs(matching_channels) - 1;
+
+		drm_dbg(dev, "Assigned HVS channel %d to CRTC %s\n", channel, crtc->name);
 		new_vc4_crtc_state->assigned_channel = channel;
 		unassigned_channels &= ~BIT(channel);
 		hvs_new_state->fifo_state[channel].in_use = true;