[Intel-gfx] [PATCH v3 5/8] drm/i915: Check error return when converting pipe to connector

[Ville Syrjälä]

On Thu, Apr 27, 2017 at 11:36:54AM +0300, Imre Deak wrote:
> An error from intel_get_pipe_from_connector() would mean a bug somewhere
> else, but we still should check for it to prevent some other more
> obscure bug later.
> 
> v2:
> - Fall back to a reasonable default instead of bailing out in case of
>   error. (Jani)
> v3:
> - Fix s/PIPE_INVALID/INVALID_PIPE/ typo. (Jani)
> 
> Cc: Jani Nikula <jani.nikula at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_panel.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index cb50c52..d1abbf1 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -888,10 +888,14 @@ static void pch_enable_backlight(struct intel_connector *connector)
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  	struct intel_panel *panel = &connector->panel;
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
> -	enum transcoder cpu_transcoder =
> -		intel_pipe_to_cpu_transcoder(dev_priv, pipe);
> +	enum transcoder cpu_transcoder;
>  	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
>  
> +	if (!WARN_ON_ONCE(pipe == INVALID_PIPE))
> +		cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv, pipe);
> +	else
> +		cpu_transcoder = TRANSCODER_EDP;
> +
>  	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
>  	if (cpu_ctl2 & BLM_PWM_ENABLE) {
>  		DRM_DEBUG_KMS("cpu backlight already enabled\n");
> @@ -973,6 +977,9 @@ static void i965_enable_backlight(struct intel_connector *connector)
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
>  	u32 ctl, ctl2, freq;
>  
> +	if (WARN_ON_ONCE(pipe == INVALID_PIPE))
> +		pipe = PIPE_A;
> +
>  	ctl2 = I915_READ(BLC_PWM_CTL2);
>  	if (ctl2 & BLM_PWM_ENABLE) {
>  		DRM_DEBUG_KMS("backlight already enabled\n");
> @@ -1037,6 +1044,9 @@ static void bxt_enable_backlight(struct intel_connector *connector)
>  	enum pipe pipe = intel_get_pipe_from_connector(connector);
>  	u32 pwm_ctl, val;
>  
> +	if (WARN_ON_ONCE(pipe) == INVALID_PIPE)
                             ^

Isn't that thing in the wrong place?

> +		pipe = PIPE_A;
> +
>  	/* Controller 1 uses the utility pin. */
>  	if (panel->backlight.controller == 1) {
>  		val = I915_READ(UTIL_PIN_CTL);
> @@ -1093,7 +1103,8 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
>  	if (!panel->backlight.present)
>  		return;
>  
> -	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
> +	if (!WARN_ON_ONCE(pipe == INVALID_PIPE))
> +		DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
>  
>  	mutex_lock(&dev_priv->backlight_lock);
>  
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC