Re: [PATCH 7/7] drm/i915/dp: Limit brightness level to 20

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 04 Apr 2024, Suraj Kandpal <suraj.kandpal@intel.com> wrote:
> Limit minimum brightness to 20 when using aux based brightness
> control to avoid letting the screen going completely blank.

Why "20"? What does it mean? Why don't we have this in the VBT like for
PWM backlight?

>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> 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 20dd5a6a0f3f..b54ea7e46954 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -211,6 +211,9 @@ intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state,
>  	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
>  	u8 buf[4] = {};
>  
> +	if (level < 20)
> +		level = 20;
> +
>  	buf[0] = level & 0xFF;
>  	buf[1] = (level & 0xFF00) >> 8;

-- 
Jani Nikula, Intel