[Intel-gfx] [PATCH v5 1/9] drm/i915: Fix cap check for intel_dp_aux_backlight driver

[Pandiyan, Dhinakaran]

On Wed, 2017-05-03 at 17:28 -0700, Puthikorn Voravootivat wrote:
> intel_dp_aux_backlight driver should check for the
> DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP before enable the driver.
> 
> Signed-off-by: Puthikorn Voravootivat <puthik at chromium.org>
> ---
>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> index 6532e226db29..24a905d1a74b 100644
> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> @@ -142,10 +142,9 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
>  	/* Check the  eDP Display control capabilities registers to determine if
>  	 * the panel can support backlight control over the aux channel
>  	 */
> -	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
> +	if ((intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP) &&
>  	    (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
> -	    !((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
> -	      (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {

^Were these two changes intended? The patch claims an additional check
for DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP is being added but also
makes this unrelated change. Aren't you changing how the driver
prioritizes AUX v/s PWM brightness control by removing these lines?

-DK


> +	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
>  		DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
>  		return true;
>  	}