Sending DSI commands from the prepare() callback requires DSI link to be
up at that point. For DSI hosts is guaranteed only if the panel driver
sets the .prepare_prev_first flag. Set it to let these panels work with
the DSI hosts which don't power on the link in their .mode_set callback.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/panel/panel-himax-hx8394.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-himax-hx8394.c b/drivers/gpu/drm/panel/panel-himax-hx8394.c
index c4d3e09a228d..d64f3521eb15 100644
--- a/drivers/gpu/drm/panel/panel-himax-hx8394.c
+++ b/drivers/gpu/drm/panel/panel-himax-hx8394.c
@@ -792,6 +792,8 @@ static int hx8394_probe(struct mipi_dsi_device *dsi)
 	if (ret)
 		return ret;
 
+	ctx->panel.prepare_prev_first = true;
+
 	drm_panel_add(&ctx->panel);
 
 	ret = mipi_dsi_attach(dsi);

-- 
2.47.3