[Intel-gfx] [PATCH v3] drm/i915: Check backlight type while doing eDP backlight initializaiton

[Lee, Shawn C]

On Tue, 25 Jun 2019, Jani Nikula <jani.nikula at intel.com> wrote:
>On Thu, 20 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.
>> v3: 1. Modify i915.enable_dpcd_backlight type from bool to int and give default
>>        value as 0 (disable).
>
>I was thinking we'd change the default to -1 to trust the VBT, but might be just as well to start with this and change the default later.
>
>CI flagged errors for some reasons, I've queued a retest. I don't think it was caused by this patch.
>
>Reviewed-by: Jani Nikula <jani.nikula at intel.com>
>

Agree with your comments. That's why we keep the default value to 0. We can change the default in the future if necessary.
Thanks for review.

>
>>     2. Add a judgement to check LFP backlight type was aux interface or not.
>>
>> 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 | 5 ++++-
>>  drivers/gpu/drm/i915/i915_params.c                    | 5 +++--
>>  drivers/gpu/drm/i915/i915_params.h                    | 2 +-
>>  4 files changed, 9 insertions(+), 4 deletions(-)
>>
>> 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..6b0b73479fb8 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 +264,11 @@ 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 == 0 ||
>> +	    (i915_modparams.enable_dpcd_backlight == -1 &&
>> +	    dev_priv->vbt.backlight.type != 
>> +INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE))
>>  		return -ENODEV;
>>  
>>  	if (!intel_dp_aux_display_control_capable(intel_connector))
>> diff --git a/drivers/gpu/drm/i915/i915_params.c 
>> b/drivers/gpu/drm/i915/i915_params.c
>> index 5b07766a1c26..296452f9efe4 100644
>> --- a/drivers/gpu/drm/i915/i915_params.c
>> +++ b/drivers/gpu/drm/i915/i915_params.c
>> @@ -169,8 +169,9 @@ i915_param_named_unsafe(inject_load_failure, uint, 0400,
>>  	"Force an error after a number of failure check points (0:disabled 
>> (default), N:force failure at the Nth failure check point)");  #endif
>>  
>> -i915_param_named(enable_dpcd_backlight, bool, 0600,
>> -	"Enable support for DPCD backlight control (default:false)");
>> +i915_param_named(enable_dpcd_backlight, int, 0600,
>> +	"Enable support for DPCD backlight control"
>> +	"(-1=use per-VBT LFP backlight type setting, 0=disabled [default], 
>> +1=enabled)");
>>  
>>  #if IS_ENABLED(CONFIG_DRM_I915_GVT)
>>  i915_param_named(enable_gvt, bool, 0400, diff --git 
>> a/drivers/gpu/drm/i915/i915_params.h 
>> b/drivers/gpu/drm/i915/i915_params.h
>> index a4770ce46bd2..d29ade3b7de6 100644
>> --- a/drivers/gpu/drm/i915/i915_params.h
>> +++ b/drivers/gpu/drm/i915/i915_params.h
>> @@ -64,6 +64,7 @@ struct drm_printer;
>>  	param(int, reset, 2) \
>>  	param(unsigned int, inject_load_failure, 0) \
>>  	param(int, fastboot, -1) \
>> +	param(int, enable_dpcd_backlight, 0) \
>>  	param(char *, force_probe, CONFIG_DRM_I915_FORCE_PROBE) \
>>  	/* leave bools at the end to not create holes */ \
>>  	param(bool, alpha_support, 
>> IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \ @@ -76,7 +77,6 @@ struct drm_printer;
>>  	param(bool, verbose_state_checks, true) \
>>  	param(bool, nuclear_pageflip, false) \
>>  	param(bool, enable_dp_mst, true) \
>> -	param(bool, enable_dpcd_backlight, false) \
>>  	param(bool, enable_gvt, false)
>>  
>>  #define MEMBER(T, member, ...) T member;
>
>--
>Jani Nikula, Intel Open Source Graphics Center
>