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

[Jani Nikula]

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>


>     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