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authorVille Syrjälä <ville.syrjala@linux.intel.com>2014-11-07 15:18:45 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2014-11-14 10:29:19 +0100
commit2d72f6c7be9cd26485f88961f6a56fae3d9d17e9 (patch)
tree60b58af15ee2d193825f59262a2a367287191b94 /drivers/gpu/drm/i915/intel_panel.c
parent23ec0a8835f38c6e43570b54a786e058a9b9a268 (diff)
drm/i915: Skip .get_backlight() when backlight isn't enabled
On VLV/CHV when the display is off, we can't read out the current backlight level from the hardware since we have no pipe to do so. Currently we end up reading a bigus register due to passing INVALID_PIPE to VLV_BLC_PWM_CTL(). Skip the entire .get_backlight() call if the backlight isn't enabled according to backlight.enabled. This problem can be reproduced simply by reading the backlight device actual_brightness file while the display is off. Cc: Jani Nikula <jani.nikula@intel.com> Suggested-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_panel.c')
-rw-r--r--drivers/gpu/drm/i915/intel_panel.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index ef646b139c4e..4ec6c2feef42 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -539,12 +539,15 @@ static u32 intel_panel_get_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
- u32 val;
+ struct intel_panel *panel = &connector->panel;
+ u32 val = 0;
mutex_lock(&dev_priv->backlight_lock);
- val = dev_priv->display.get_backlight(connector);
- val = intel_panel_compute_brightness(connector, val);
+ if (panel->backlight.enabled) {
+ val = dev_priv->display.get_backlight(connector);
+ val = intel_panel_compute_brightness(connector, val);
+ }
mutex_unlock(&dev_priv->backlight_lock);