[PATCH 4.16 140/161] media: v4l: vsp1: Fix display stalls when requesting too many inputs

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>

[ Upstream commit 5e3e4cb5e24b92773b194aa90066170b12133bc6 ]

Make sure we don't accept more inputs than the hardware can handle. This
is a temporary fix to avoid display stall, we need to instead allocate
the BRU or BRS to display pipelines dynamically based on the number of
planes they each use.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/media/platform/vsp1/vsp1_drm.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/media/platform/vsp1/vsp1_drm.c
+++ b/drivers/media/platform/vsp1/vsp1_drm.c
@@ -530,6 +530,15 @@ void vsp1_du_atomic_flush(struct device
 		struct vsp1_rwpf *rpf = vsp1->rpf[i];
 		unsigned int j;
 
+		/*
+		 * Make sure we don't accept more inputs than the hardware can
+		 * handle. This is a temporary fix to avoid display stall, we
+		 * need to instead allocate the BRU or BRS to display pipelines
+		 * dynamically based on the number of planes they each use.
+		 */
+		if (pipe->num_inputs >= pipe->bru->source_pad)
+			pipe->inputs[i] = NULL;
+
 		if (!pipe->inputs[i])
 			continue;