drm/msm/dp: Support the eDP modes given by panel

The eDP controller does not have a reliable way keep panel
powered on to read the sink capabilities. So, the controller
driver cannot validate if a mode can be supported by the
source. We will rely on the panel driver to populate only
the supported modes for now.
Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/483313/
Link: https://lore.kernel.org/r/1650887072-16652-5-git-send-email-quic_sbillaka@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/dp/dp_display.c

@@ -980,6 +980,14 @@ enum drm_mode_status dp_bridge_mode_valid(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
+	/*
+	 * The eDP controller currently does not have a reliable way of
+	 * enabling panel power to read sink capabilities. So, we rely
+	 * on the panel driver to populate only supported modes for now.
+	 */
+	if (dp->is_edp)
+		return MODE_OK;
+
 	if (mode->clock > DP_MAX_PIXEL_CLK_KHZ)
 		return MODE_BAD;