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Commit 28dcc2d6 authored by Jani Nikula's avatar Jani Nikula Committed by Daniel Vetter
Browse files

drm/i915: do not expose a dysfunctional backlight interface to userspace 



Previously intel_panel_setup_backlight() would create a sysfs backlight
interface with max brightness of 1 if it was unable to figure out the max
backlight brightness. This rendered the backlight interface useless.

Do not create a dysfunctional backlight interface to begin with.

Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Tested-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent fcbc50da

drivers/gpu/drm/i915/intel_panel.c

+22 −9
Original line number Original line Diff line number Diff line
@@ -162,19 +162,12 @@ static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv) 
	return val;

	return val;

}

}





u32 intel_panel_get_max_backlight(struct drm_device *dev)

static u32 _intel_panel_get_max_backlight(struct drm_device *dev)

{

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_private *dev_priv = dev->dev_private;

	u32 max;

	u32 max;





	max = i915_read_blc_pwm_ctl(dev_priv);

	max = i915_read_blc_pwm_ctl(dev_priv);

	if (max == 0) {

		/* XXX add code here to query mode clock or hardware clock

		 * and program max PWM appropriately.

		 */

		pr_warn_once("fixme: max PWM is zero\n");

		return 1;

	}





	if (HAS_PCH_SPLIT(dev)) {

	if (HAS_PCH_SPLIT(dev)) {

		max >>= 16;

		max >>= 16;
@@ -188,6 +181,22 @@ u32 intel_panel_get_max_backlight(struct drm_device *dev) 
			max *= 0xff;

			max *= 0xff;

	}

	}





	return max;

}



u32 intel_panel_get_max_backlight(struct drm_device *dev)

{

	u32 max;



	max = _intel_panel_get_max_backlight(dev);

	if (max == 0) {

		/* XXX add code here to query mode clock or hardware clock

		 * and program max PWM appropriately.

		 */

		pr_warn_once("fixme: max PWM is zero\n");

		return 1;

	}



	DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);

	DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);

	return max;

	return max;

}

}
@@ -424,7 +433,11 @@ int intel_panel_setup_backlight(struct drm_device *dev) 




	memset(&props, 0, sizeof(props));

	memset(&props, 0, sizeof(props));

	props.type = BACKLIGHT_RAW;

	props.type = BACKLIGHT_RAW;

	props.max_brightness = intel_panel_get_max_backlight(dev);

	props.max_brightness = _intel_panel_get_max_backlight(dev);

	if (props.max_brightness == 0) {

		DRM_ERROR("Failed to get maximum backlight value\n");

		return -ENODEV;

	}

	dev_priv->backlight =

	dev_priv->backlight =

		backlight_device_register("intel_backlight",

		backlight_device_register("intel_backlight",

					  &connector->kdev, dev,

					  &connector->kdev, dev,