[Intel-gfx] [PATCH v2] drm/i915: Check backlight type while doing eDP backlight initializaiton

[Lee, Shawn C]

On Wed, 19 Jun 2019, Jani Nikula <jani.nikula at intel.com> wrote:
>On Wed, 19 Jun 2019, Lee Shawn C <shawn.c.lee at intel.com> wrote:
>> If LFP backlight type setting from VBT was "VESA eDP AUX Interface".
>> Driver should check panel capability and try to initialize aux backlight.
>> No matter i915_modparams.enable_dpcd_backlight was enabled or not.
>>
>> v2: access dev_priv->vbt.backlight.type directly and remove unused function.
>>
>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Cc: Jose Roberto de Souza <jose.souza at intel.com>
>> Cc: Cooper Chiou <cooper.chiou at intel.com>
>>
>> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_bios.h             | 1 +
>>  drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 4 +++-
>>  2 files changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_bios.h 
>> b/drivers/gpu/drm/i915/display/intel_bios.h
>> index 4e42cfaf61a7..0b7be6389a07 100644
>> --- a/drivers/gpu/drm/i915/display/intel_bios.h
>> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
>> @@ -42,6 +42,7 @@ enum intel_backlight_type {
>>  	INTEL_BACKLIGHT_DISPLAY_DDI,
>>  	INTEL_BACKLIGHT_DSI_DCS,
>>  	INTEL_BACKLIGHT_PANEL_DRIVER_INTERFACE,
>> +	INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE,
>>  };
>>  
>>  struct edp_power_seq {
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c 
>> b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>> index 7ded95a334db..db7c7b9f9b56 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>> @@ -264,8 +264,10 @@ intel_dp_aux_display_control_capable(struct 
>> intel_connector *connector)  int 
>> intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)  {
>>  	struct intel_panel *panel = &intel_connector->panel;
>> +	struct drm_i915_private *dev_priv = 
>> +to_i915(intel_connector->base.dev);
>>  
>> -	if (!i915_modparams.enable_dpcd_backlight)
>> +	if (!i915_modparams.enable_dpcd_backlight &&
>> +	    (dev_priv->vbt.backlight.type != 
>> +INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE))
>>  		return -ENODEV;
>
>There was also this part in the v1 review:
>
>    The usual thing to do is to set i915.enable_dpcd_backlight initial value
>    to -1 (i.e. make it an int), and with that default value respect
>    VBT. Otherwise, respect the value of enable_dpcd_backlight.
>
>
>BR,
>Jani.

Do you mean we should do following?
1. Change i915.enable_dpcd_backlight type from bool to int.
2. Give default value as -1 for enable_dpcd_backlight in i915_param.h.
3. Add a judgement to check LFP backlight type was aux interface or not.
   Between if (!i915_modparams.enable_dpcd_backlight) and 
   if (!intel_dp_aux_display_control_capable(intel_connector)).

Best regards,
Shawn

>>  
>>  	if (!intel_dp_aux_display_control_capable(intel_connector))
>
>--
>Jani Nikula, Intel Open Source Graphics Center