[PATCH AUTOSEL 6.18-6.6] drm/panel: jadard-jd9365da-h3: set prepare_prev_first

[Sasha Levin]

From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>

[ Upstream commit b55a4b5d4769a650f52ea3f1ae680610169d125e ]

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.

Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
Tested-by: Riccardo Mereu <r.mereu@xxxxxxxxxx>
Link: https://patch.msgid.link/20260413-waveshare-dsi-touch-v3-13-3aeb53022c32@xxxxxxxxxxxxxxxx
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---

LLM Generated explanations, may be completely bogus:

The background `git log -S'panel-jadard-jd9365da-h3'` search finished
(took ~3 minutes). It only surfaced merge commits — the first hit is
`5d324e5159d9e` (usb-6.18-rc8 merge) — which matches what we saw
earlier: this stable tree’s history doesn’t give a clean upstream
“driver added in commit X” trail.

That doesn’t change the backport assessment. The driver is present in
6.18.43, the bug (missing `prepare_prev_first`) is confirmed, the patch
applies cleanly, and the verdict remains **YES**.

 drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
index 5c2530598ddb9..9e5287829b952 100644
--- a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
+++ b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
@@ -1157,6 +1157,8 @@ static int jadard_dsi_probe(struct mipi_dsi_device *dsi)
 	if (ret)
 		return ret;
 
+	jadard->panel.prepare_prev_first = true;
+
 	drm_panel_add(&jadard->panel);
 
 	mipi_dsi_set_drvdata(dsi, jadard);
-- 
2.53.0