drm/i915: Add breadcrumbs for why the backlight is being set

At the moment we have 3 paths that lead to actually_set_backlight(),
from modesetting, ACPI/OpRegion requests and our very own
intel_backlight interface, and we have no way of distinguishing them in
the debug log. So add a debug breadcrumb to explain the source of the
backlight changes.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index 9044640..b82050c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -407,6 +407,7 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
        if (bclp > 255)
                return ASLC_BACKLIGHT_FAILED;
 
+       DRM_DEBUG_KMS("updating opregion backlight %d/255\n", bclp);
        intel_panel_set_backlight(dev, bclp, 255);
        iowrite32(DIV_ROUND_UP(bclp * 100, 255) | ASLE_CBLV_VALID, &asle->cblv);
 

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 5468416..1f29960 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -574,6 +574,8 @@ void intel_panel_enable_backlight(struct drm_device *dev,
                intel_pipe_to_cpu_transcoder(dev_priv, pipe);
        unsigned long flags;
 
+       DRM_DEBUG_KMS("pipe=%d\n", pipe);
+
        spin_lock_irqsave(&dev_priv->backlight.lock, flags);
 
        if (dev_priv->backlight.level == 0) {
@@ -680,6 +682,8 @@ intel_panel_detect(struct drm_device *dev)
 static int intel_panel_update_status(struct backlight_device *bd)
 {
        struct drm_device *dev = bl_get_data(bd);
+       DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
+                     bd->props.brightness, bd->props.max_brightness);
        intel_panel_set_backlight(dev, bd->props.brightness,
                                  bd->props.max_brightness);
        return 0;