[PATCH 1/2] drm/i915/dpcd_bl: uncheck PWM_PIN_CAP when detect eDP backlight capabilities

[Lyude Paul]

Completely zoned out on Ccing these patches to stable before submitting them,
but once they hit the mainline kernel you should be able to ask Greg to backport
them if you need. Anyway, pushed to drm-intel-next-queued. Thanks for the
patches!

On Fri, 2020-10-09 at 16:57 +0800, Aaron Ma wrote:
> BOE panel with ID 2270 claims both PWM_PIN_CAP and AUX_SET_CAP backlight
> control bits, but default chip backlight failed to control brightness.
> 
> Check AUX_SET_CAP and proceed to check quirks or VBT backlight type.
> DPCD can control the brightness of this pannel.
> 
> Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> 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 acbd7eb66cbe..308b14159b7c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -334,8 +334,7 @@ intel_dp_aux_display_control_capable(struct
> intel_connector *connector)
>  	 * the panel can support backlight control over the aux channel
>  	 */
>  	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
> -	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
> -	    !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))
> {
> +	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
>  		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
>  		return true;
>  	}
-- 
Sincerely,
      Lyude Paul (she/her)
      Software Engineer at Red Hat

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