drm/i915: Make backlight setup debugs consistent

It's confusing to debug backlight issues when one can't
easily even tell what kind of backlight control was
selected. Sprinkle uniform debug messages to all the
backlight setup functions.

Also the one that was already there (ext_pwm) was
using drm_info() for some reason. I don't think that's
warranted so switch it to drm_dbg_kms() as well.

v2: Deal with AUX backlights too (Jani)
    Move the VLV/CHV initial pipe debug there too (Jani)

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230215135616.30411-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 34 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index a4e4b7f79e4d..cb1e4423decb 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -1270,6 +1270,10 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
 			       cpu_ctl2 & ~BLM_PWM_ENABLE);
 	}
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PCH PWM for backlight control\n",
+		    connector->base.base.id, connector->base.name);
+
 	return 0;
 }
 
@@ -1297,6 +1301,10 @@ static int pch_setup_backlight(struct intel_connector *connector, enum pipe unus
 	panel->backlight.pwm_enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
 		(pch_ctl1 & BLM_PCH_PWM_ENABLE);
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PCH PWM for backlight control\n",
+		    connector->base.base.id, connector->base.name);
+
 	return 0;
 }
 
@@ -1335,6 +1343,10 @@ static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unu
 
 	panel->backlight.pwm_enabled = val != 0;
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PWM for backlight control\n",
+		    connector->base.base.id, connector->base.name);
+
 	return 0;
 }
 
@@ -1364,6 +1376,10 @@ static int i965_setup_backlight(struct intel_connector *connector, enum pipe unu
 
 	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PWM for backlight control\n",
+		    connector->base.base.id, connector->base.name);
+
 	return 0;
 }
 
@@ -1392,6 +1408,10 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
 
 	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PWM for backlight control (on pipe %c)\n",
+		    connector->base.base.id, connector->base.name, pipe_name(pipe));
+
 	return 0;
 }
 
@@ -1428,6 +1448,11 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
 
 	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PWM for backlight control (controller=%d)\n",
+		    connector->base.base.id, connector->base.name,
+		    panel->backlight.controller);
+
 	return 0;
 }
 
@@ -1490,6 +1515,11 @@ cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)
 
 	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
 
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using native PCH PWM for backlight control (controller=%d)\n",
+		    connector->base.base.id, connector->base.name,
+		    panel->backlight.controller);
+
 	return 0;
 }
 
@@ -1538,8 +1568,10 @@ static int ext_pwm_setup_backlight(struct intel_connector *connector,
 			NSEC_PER_SEC / get_vbt_pwm_freq(connector);
 	}
 
-	drm_info(&i915->drm, "Using %s PWM for LCD backlight control\n",
-		 desc);
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] Using %s PWM for backlight control\n",
+		    connector->base.base.id, connector->base.name, desc);
+
 	return 0;
 }