drm/amd/display: If one stream full updates, full update all planes

[Why]
On some compositors, with two monitors attached, VT terminal
switch can cause a graphical issue by the following means:

There are two streams, one for each monitor. Each stream has one
plane

current state:
	M1:S1->P1
	M2:S2->P2

The user calls for a terminal switch and a commit is made to
change both planes to linear swizzle mode. In atomic check,
a new dc_state is constructed with new planes on each stream

new state:
	M1:S1->P3
	M2:S2->P4

In commit tail, each stream is committed, one at a time. The first
stream (S1) updates properly, triggerring a full update and replacing
the state

current state:
	M1:S1->P3
	M2:S2->P4

The update for S2 comes in, but dc detects that there is no difference
between the stream and plane in the new and current states, and so
triggers a fast update. The fast update does not program swizzle,
so the second monitor is corrupted

[How]
Add a flag to dc_plane_state that forces full updates

When a stream undergoes a full update, set this flag on all changed
planes, then clear it on the current stream

Subsequent streams will get full updates as a result

Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Roman Li <Roman.Li@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet Lakha@amd.com>
Acked-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index 1a7fd6aa77eb..0515095574e7 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -503,6 +503,9 @@ struct dc_plane_state {
 	struct dc_plane_status status;
 	struct dc_context *ctx;
 
+	/* HACK: Workaround for forcing full reprogramming under some conditions */
+	bool force_full_update;
+
 	/* private to dc_surface.c */
 	enum dc_irq_source irq_source;
 	struct kref refcount;