linux-kernel - [PATCH 1/8] drm/panel: himax-hx8394: Handle errors from mipi_dsi_dcs_set_display

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Date: Fri, 17 May 2024 14:36:36 -0700
From: Douglas Anderson <dianders@...omium.org>
To: Neil Armstrong <neil.armstrong@...aro.org>,
	Jessica Zhang <quic_jesszhan@...cinc.com>,
	Sam Ravnborg <sam@...nborg.org>
Cc: Linus Walleij <linus.walleij@...aro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Douglas Anderson <dianders@...omium.org>,
	Daniel Vetter <daniel@...ll.ch>,
	David Airlie <airlied@...il.com>,
	Javier Martinez Canillas <javierm@...hat.com>,
	Kamil Trzciński <ayufan@...fan.eu>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Ondrej Jirman <megi@....cz>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/8] 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@...omium.org>
---

 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 ff0dc08b9829..cb9f46e853de 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;
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog