From cc2db2ef8d9eebc0df03808ac0dadbdb96733499 Mon Sep 17 00:00:00 2001
From: Douglas Anderson <dianders@chromium.org>
Date: Fri, 17 May 2024 14:36:36 -0700
Subject: [PATCH] drm/panel: himax-hx8394: Handle errors from
 mipi_dsi_dcs_set_display_on() better

If mipi_dsi_dcs_set_display_on() returned an error then we'd store
that in the "ret" variable and jump to error handling. We'd then
attempt an orderly poweroff. Unfortunately we then blew away the value
stored in "ret". That means that if the orderly poweroff actually
worked then we're return 0 (no error) from hx8394_enable() even though
the panel wasn't enabled.

Fix this by not blowing away "ret".

Found by code inspection.

Fixes: 65dc9360f741 ("drm: panel: Add Himax HX8394 panel controller driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240517143643.1.I0a6836fffd8d7620f353becb3df2370d2898f803@changeid
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517143643.1.I0a6836fffd8d7620f353becb3df2370d2898f803@changeid
---
 drivers/gpu/drm/panel/panel-himax-hx8394.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-himax-hx8394.c b/drivers/gpu/drm/panel/panel-himax-hx8394.c
index ff0dc08b98297..cb9f46e853de4 100644
--- a/drivers/gpu/drm/panel/panel-himax-hx8394.c
+++ b/drivers/gpu/drm/panel/panel-himax-hx8394.c
@@ -370,8 +370,7 @@ static int hx8394_enable(struct drm_panel *panel)
 
 sleep_in:
 	/* This will probably fail, but let's try orderly power off anyway. */
-	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
-	if (!ret)
+	if (!mipi_dsi_dcs_enter_sleep_mode(dsi))
 		msleep(50);
 
 	return ret;
-- 
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