[Intel-gfx] [PATCH 5/8] drm/i915: Check error return when converting pipe to connector

[Imre Deak]

An error from intel_get_pipe_from_connector() would mean a bug somewhere
else, but we still should check for it to prevent some other more
obscure bug later.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_panel.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index cb50c52..dbe05ec 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -888,10 +888,14 @@ static void pch_enable_backlight(struct intel_connector *connector)
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	struct intel_panel *panel = &connector->panel;
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
-	enum transcoder cpu_transcoder =
-		intel_pipe_to_cpu_transcoder(dev_priv, pipe);
+	enum transcoder cpu_transcoder;
 	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
 
+	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
+		return;
+
+	cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv, pipe);
+
 	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
 	if (cpu_ctl2 & BLM_PWM_ENABLE) {
 		DRM_DEBUG_KMS("cpu backlight already enabled\n");
@@ -973,6 +977,9 @@ static void i965_enable_backlight(struct intel_connector *connector)
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
 	u32 ctl, ctl2, freq;
 
+	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
+		return;
+
 	ctl2 = I915_READ(BLC_PWM_CTL2);
 	if (ctl2 & BLM_PWM_ENABLE) {
 		DRM_DEBUG_KMS("backlight already enabled\n");
@@ -1093,6 +1100,9 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 	if (!panel->backlight.present)
 		return;
 
+	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
+		return;
+
 	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
 
 	mutex_lock(&dev_priv->backlight_lock);
-- 
2.5.0