drm/i915: Skip .get_backlight() when backlight isn't enabled

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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>

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This commit is contained in:

Ville Syrjälä 2014-11-07 15:18:45 +02:00 • committed by Daniel Vetter

parent 23ec0a8835

commit 2d72f6c7be

1 changed files with 6 additions and 3 deletions

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drivers/gpu/drm/i915/intel_panel.c

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