Re: [PATCH 1/6] drm/i915: Warn if trying to poke a VLV backlight on invalid pipe

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 07 Nov 2014, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> VLV/CHV have backlight controls only on pipes A and B. Bail out
> without touching registers that don't exist, and print a warning.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_panel.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index e18b3f4..ef646b1 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -521,6 +521,9 @@ static u32 _vlv_get_backlight(struct drm_device *dev, enum pipe pipe)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> +	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> +		return 0;
> +
>  	return I915_READ(VLV_BLC_PWM_CTL(pipe)) & BACKLIGHT_DUTY_CYCLE_MASK;
>  }
>  
> @@ -602,6 +605,9 @@ static void vlv_set_backlight(struct intel_connector *connector, u32 level)
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
>  	u32 tmp;
>  
> +	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> +		return;
> +
>  	tmp = I915_READ(VLV_BLC_PWM_CTL(pipe)) & ~BACKLIGHT_DUTY_CYCLE_MASK;
>  	I915_WRITE(VLV_BLC_PWM_CTL(pipe), tmp | level);
>  }
> @@ -717,6 +723,9 @@ static void vlv_disable_backlight(struct intel_connector *connector)
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
>  	u32 tmp;
>  
> +	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> +		return;
> +
>  	intel_panel_actually_set_backlight(connector, 0);
>  
>  	tmp = I915_READ(VLV_BLC_PWM_CTL2(pipe));
> @@ -906,6 +915,9 @@ static void vlv_enable_backlight(struct intel_connector *connector)
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
>  	u32 ctl, ctl2;
>  
> +	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> +		return;
> +
>  	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
>  	if (ctl2 & BLM_PWM_ENABLE) {
>  		DRM_DEBUG_KMS("backlight already enabled\n");
> -- 
> 2.0.4
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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