Commit 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
introduced logic to unregister DSI1 on any sort of probe failure, as
that's not done automatically by kernel APIs.

It did not however account for cases where only one DSI host is used.
Fix that.

Fixes: 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
Reported-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/gpu/drm/panel/panel-novatek-nt35950.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-novatek-nt35950.c b/drivers/gpu/drm/panel/panel-novatek-nt35950.c
index 7498fc6258bb..8b108ac80b55 100644
--- a/drivers/gpu/drm/panel/panel-novatek-nt35950.c
+++ b/drivers/gpu/drm/panel/panel-novatek-nt35950.c
@@ -586,7 +586,8 @@ static int nt35950_probe(struct mipi_dsi_device *dsi)
 
 	ret = drm_panel_of_backlight(&nt->panel);
 	if (ret) {
-		mipi_dsi_device_unregister(nt->dsi[1]);
+		if (num_dsis == 2)
+			mipi_dsi_device_unregister(nt->dsi[1]);
 
 		return dev_err_probe(dev, ret, "Failed to get backlight\n");
 	}
@@ -606,7 +607,8 @@ static int nt35950_probe(struct mipi_dsi_device *dsi)
 		ret = mipi_dsi_attach(nt->dsi[i]);
 		if (ret < 0) {
 			/* If we fail to attach to either host, we're done */
-			mipi_dsi_device_unregister(nt->dsi[1]);
+			if (num_dsis == 2)
+				mipi_dsi_device_unregister(nt->dsi[1]);
 
 			return dev_err_probe(dev, ret,
 					     "Cannot attach to DSI%d host.\n", i);

---
base-commit: ab4f869fba6119997f7630d600049762a2b014fa
change-id: 20230417-topic-maple_panel_fixup-170b6d3a8c9b

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@linaro.org>

Hi,

On Mon, 17 Apr 2023 17:41:08 +0200, Konrad Dybcio wrote:
> Commit 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
> introduced logic to unregister DSI1 on any sort of probe failure, as
> that's not done automatically by kernel APIs.
> 
> It did not however account for cases where only one DSI host is used.
> Fix that.
> 
> [...]

Thanks, Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next-fixes)

[1/1] drm/panel: novatek-nt35950: Only unregister DSI1 if it exists
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=a50be876f4fe2349dc8b056a49d87f69c944570f

-- 
Neil

Il 17/04/23 17:41, Konrad Dybcio ha scritto:
> Commit 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
> introduced logic to unregister DSI1 on any sort of probe failure, as
> that's not done automatically by kernel APIs.
> 
> It did not however account for cases where only one DSI host is used.
> Fix that.
> 
> Fixes: 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
> Reported-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>