[v2,2/3] drm/i915: Force DPCD backlight mode on X1 Extreme 2nd Gen 4K AMOLED panel

[Adam Jackson]

On Tue, 2020-02-11 at 13:33 -0500, Lyude Paul wrote:

> -	if (!intel_dp_aux_display_control_capable(intel_connector))
> +	/*
> +	 * There are a lot of machines that don't advertise the backlight
> +	 * control interface to use properly in their VBIOS, :\
> +	 */
> +	if (dev_priv->vbt.backlight.type !=
> +	    INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE &&
> +	    !drm_dp_has_quirk(&intel_dp->desc, intel_dp->edid_quirks,
> +			      DP_QUIRK_FORCE_DPCD_BACKLIGHT)) {
> +		DRM_DEV_INFO(dev->dev,
> +			     "Panel advertises DPCD backlight support, but "
> +			     "VBT disagrees. If your backlight controls "
> +			     "don't work try booting with "
> +			     "i915.enable_dpcd_backlight=1. If your machine "
> +			     "needs this, please file a _new_ bug report on "
> +			     "bugs.freedesktop.org against DRI -> "
> +			     "DRM/Intel\n");

Bugzilla's been put out of our misery, probably this should point to
gitlab instead.

- ajax