[v4,09/10] drm/vc4: Add logging and comments

Commit Message

Maxime Ripard Jan. 25, 2022, 2:15 p.m. UTC

The HVS core clock isn't really obvious, so let's add a bunch more
comments and some logging for easier debugging.

Signed-off-by: Maxime Ripard <[e-mail]>
---
 drivers/gpu/drm/vc4/vc4_kms.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 24de29bc1cda..6fe03fc17d73 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -389,8 +389,15 @@  static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 						500000000,
 						new_hvs_state->core_clock_rate);
 
+		drm_dbg(dev, "Raising the core clock at %lu Hz\n", core_rate);
+
+		/*
+		 * Do a temporary request on the core clock during the
+		 * modeset.
+		 */
 		clk_set_min_rate(hvs->core_clk, core_rate);
 	}
+
 	drm_atomic_helper_commit_modeset_disables(dev, state);
 
 	vc4_ctm_commit(vc4, state);
@@ -416,6 +423,10 @@  static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 		drm_dbg(dev, "Running the core clock at %lu Hz\n",
 			new_hvs_state->core_clock_rate);
 
+		/*
+		 * Request a clock rate based on the current HVS
+		 * requirements.
+		 */
 		clk_set_min_rate(hvs->core_clk, new_hvs_state->core_clock_rate);
 	}
 }