[PATCH] drm/i915: Fix audio component initialization

[Imre Deak <imre.deak@xxxxxxxxx>]

After registering the audio component in i915_audio_component_init()
the audio driver may call i915_audio_component_get_power() via the
component ops. This could program AUD_FREQ_CNTRL with an uninitialized
value if the latter function is called before display.audio.freq_cntrl
gets initialized. The get_power() function also does a modeset which in
the above case happens too early before the initialization step and
triggers the

"Reject display access from task"

error message added by the Fixes: commit below.

Fix the above issue by registering the audio component only after the
initialization step.

Fixes: 87c1694533c9 ("drm/i915: save AUD_FREQ_CNTRL state at audio domain suspend")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/10291
Cc: stable@xxxxxxxxxxxxxxx # v5.5+
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240521143022.3784539-1-imre.deak@xxxxxxxxx
(cherry picked from commit fdd0b80172758ce284f19fa8a26d90c61e4371d2)
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>

diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
index ed81e1466c4b..40e7d862675e 100644
--- a/drivers/gpu/drm/i915/display/intel_audio.c
+++ b/drivers/gpu/drm/i915/display/intel_audio.c
@@ -1252,17 +1252,6 @@ static const struct component_ops i915_audio_component_bind_ops = {
 static void i915_audio_component_init(struct drm_i915_private *i915)
 {
 	u32 aud_freq, aud_freq_init;
-	int ret;
-
-	ret = component_add_typed(i915->drm.dev,
-				  &i915_audio_component_bind_ops,
-				  I915_COMPONENT_AUDIO);
-	if (ret < 0) {
-		drm_err(&i915->drm,
-			"failed to add audio component (%d)\n", ret);
-		/* continue with reduced functionality */
-		return;
-	}
 
 	if (DISPLAY_VER(i915) >= 9) {
 		aud_freq_init = intel_de_read(i915, AUD_FREQ_CNTRL);
@@ -1285,6 +1274,21 @@ static void i915_audio_component_init(struct drm_i915_private *i915)
 
 	/* init with current cdclk */
 	intel_audio_cdclk_change_post(i915);
+}
+
+static void i915_audio_component_register(struct drm_i915_private *i915)
+{
+	int ret;
+
+	ret = component_add_typed(i915->drm.dev,
+				  &i915_audio_component_bind_ops,
+				  I915_COMPONENT_AUDIO);
+	if (ret < 0) {
+		drm_err(&i915->drm,
+			"failed to add audio component (%d)\n", ret);
+		/* continue with reduced functionality */
+		return;
+	}
 
 	i915->display.audio.component_registered = true;
 }
@@ -1317,6 +1321,12 @@ void intel_audio_init(struct drm_i915_private *i915)
 		i915_audio_component_init(i915);
 }
 
+void intel_audio_register(struct drm_i915_private *i915)
+{
+	if (!i915->display.audio.lpe.platdev)
+		i915_audio_component_register(i915);
+}
+
 /**
  * intel_audio_deinit() - deinitialize the audio driver
  * @i915: the i915 drm device private data
diff --git a/drivers/gpu/drm/i915/display/intel_audio.h b/drivers/gpu/drm/i915/display/intel_audio.h
index 9327954b801e..576c061d72a4 100644
--- a/drivers/gpu/drm/i915/display/intel_audio.h
+++ b/drivers/gpu/drm/i915/display/intel_audio.h
@@ -28,6 +28,7 @@ void intel_audio_codec_get_config(struct intel_encoder *encoder,
 void intel_audio_cdclk_change_pre(struct drm_i915_private *dev_priv);
 void intel_audio_cdclk_change_post(struct drm_i915_private *dev_priv);
 void intel_audio_init(struct drm_i915_private *dev_priv);
+void intel_audio_register(struct drm_i915_private *i915);
 void intel_audio_deinit(struct drm_i915_private *dev_priv);
 void intel_audio_sdp_split_update(const struct intel_crtc_state *crtc_state);
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c b/drivers/gpu/drm/i915/display/intel_display_driver.c
index 89bd032ed995..794b4af38055 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -540,6 +540,8 @@ void intel_display_driver_register(struct drm_i915_private *i915)
 
 	intel_display_driver_enable_user_access(i915);
 
+	intel_audio_register(i915);
+
 	intel_display_debugfs_register(i915);
 
 	/*