[PATCH v2] drm/panel: ronbo-rb070d30: Ignore DCS errors in disable()

[Hsieh Hung-En <hungen3108@gmail.com>]

If rb070d30_panel_disable() returns an error, drm_panel_disable() skips
clearing panel->enabled. unprepare() still powers the panel off, but the
next drm_panel_enable() sees the panel as already enabled and does
nothing, so the panel stays dark.

Always return 0 from disable(). A failed ENTER_SLEEP_MODE is still logged
by mipi_dsi_dcs_enter_sleep_mode_multi().

Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Hsieh Hung-En <hungen3108@gmail.com>
---

Notes:
    Changes in v2:
    - Add a comment explaining why the error is ignored (Doug)
    
    This applies on top of:
    https://lore.kernel.org/all/20260929080143.559685-1-hungen3108@gmail.com/
    
    v1:
    https://lore.kernel.org/all/20260930013029.3241267-1-hungen3108@gmail.com/
    
    Compile-tested on arm64 with W=1; not tested on hardware.

 drivers/gpu/drm/panel/panel-ronbo-rb070d30.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-ronbo-rb070d30.c b/drivers/gpu/drm/panel/panel-ronbo-rb070d30.c
index ebe6352db..9adf97aba 100644
--- a/drivers/gpu/drm/panel/panel-ronbo-rb070d30.c
+++ b/drivers/gpu/drm/panel/panel-ronbo-rb070d30.c
@@ -87,7 +87,13 @@ static int rb070d30_panel_disable(struct drm_panel *panel)
 	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
 
 	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
-	return dsi_ctx.accum_err;
+
+	/*
+	 * Returning an error would leave panel->enabled set, causing the
+	 * next enable to be skipped even after unprepare powers off the panel.
+	 * The helper above already logs any command failure.
+	 */
+	return 0;
 }
 
 /* Default timings */
-- 
2.43.0