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

From: Jani Nikula <jani.nikula@intel.com>
To: imre.deak@intel.com, "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH v3 5/8] drm/i915: Check error return when converting pipe to connector
Date: Thu, 27 Apr 2017 15:03:28 +0300	[thread overview]
Message-ID: <878tmmrran.fsf@intel.com> (raw)
In-Reply-To: <20170427115600.GC4327@ideak-desk.fi.intel.com>

On Thu, 27 Apr 2017, Imre Deak <imre.deak@intel.com> wrote:
> On Thu, Apr 27, 2017 at 02:49:55PM +0300, Ville Syrjälä wrote:
>> 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@intel.com>
>> > Signed-off-by: Imre Deak <imre.deak@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?
>
> Yes, thanks for catching it.

*facepalm* I guess my review is not to be trusted. :/

BR,
Jani.

>
>> 
>> > +		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
>> > 
>> > _______________________________________________
>> > Intel-gfx mailing list
>> > Intel-gfx@lists.freedesktop.org
>> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> 
>> -- 
>> Ville Syrjälä
>> Intel OTC

-- 
Jani Nikula, Intel Open Source Technology Center
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