[PATCH 27/45] drm/amd/display: Fix driver load crash in amdgpu_dm

[sunpeng.li at amd.com]

From: Leo Li <sunpeng.li at amd.com>

[Why]
This fixes an regression introduced by:
    drm/amd/display: add stream ID and otg instance in dc_stream_state

During driver initialization, a null pointer deref is raised. This is
caused by searching for a stream status in the dc->current_state before
the dc_state swap happens at the end of dc_commit_state_no_check().
Since the swap has not happened, the dc_state to be swapped in should
be searched, and not dc->current_state.

[How]
Add a function that searches for the stream status within the given
dc_state, instead of dc->current_state. Use that before the state swap
happens in dc_commit_state_no_check().

Also remove duplicate occurrences of this function in amdgpu_dm.c.

Signed-off-by: Leo Li <sunpeng.li at amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland at amd.com>
Acked-by: Nicholas Kazlauskas <Nicholas.Kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 22 +++-------------
 drivers/gpu/drm/amd/display/dc/core/dc.c          |  2 +-
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c   | 32 +++++++++++++++++++----
 drivers/gpu/drm/amd/display/dc/dc_stream.h        |  3 +++
 4 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index fcf8524..c0c664e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4381,20 +4381,6 @@ static void prepare_flip_isr(struct amdgpu_crtc *acrtc)
 						 acrtc->crtc_id);
 }
 
-struct dc_stream_status *dc_state_get_stream_status(
-	struct dc_state *state,
-	struct dc_stream_state *stream)
-{
-	uint8_t i;
-
-	for (i = 0; i < state->stream_count; i++) {
-		if (stream == state->streams[i])
-			return &state->stream_status[i];
-	}
-
-	return NULL;
-}
-
 static void update_freesync_state_on_stream(
 	struct amdgpu_display_manager *dm,
 	struct dm_crtc_state *new_crtc_state,
@@ -4965,8 +4951,8 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 					dc_stream_get_status(dm_new_crtc_state->stream);
 
 			if (!status)
-				status = dc_state_get_stream_status(dc_state,
-								    dm_new_crtc_state->stream);
+				status = dc_stream_get_status_from_state(dc_state,
+									 dm_new_crtc_state->stream);
 
 			if (!status)
 				DC_ERR("got no status for stream %p on acrtc%p\n", dm_new_crtc_state->stream, acrtc);
@@ -5728,8 +5714,8 @@ dm_determine_update_type_for_commit(struct dc *dc,
 					goto cleanup;
 				}
 
-				status = dc_state_get_stream_status(old_dm_state->context,
-								    new_dm_crtc_state->stream);
+				status = dc_stream_get_status_from_state(old_dm_state->context,
+									 new_dm_crtc_state->stream);
 
 				update_type = dc_check_update_surfaces_for_stream(dc, updates, num_plane,
 										  &stream_update, status);
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 575c318..c98fa8d 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1075,7 +1075,7 @@ static enum dc_status dc_commit_state_no_check(struct dc *dc, struct dc_state *c
 			}
 		}
 
-		status = dc_stream_get_status(context->streams[i]);
+		status = dc_stream_get_status_from_state(context, context->streams[i]);
 		context->streams[i]->out.otg_offset = status->primary_otg_inst;
 
 		CONN_MSG_MODE(link, "{%dx%d, %dx%d@%dKhz}",
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
index 336586b..ed5eb8a 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
@@ -160,21 +160,43 @@ struct dc_stream_state *dc_create_stream_for_sink(
 	return stream;
 }
 
-struct dc_stream_status *dc_stream_get_status(
+/**
+ * dc_stream_get_status_from_state - Get stream status from given dc state
+ * @state: DC state to find the stream status in
+ * @stream: The stream to get the stream status for
+ *
+ * The given stream is expected to exist in the given dc state. Otherwise, NULL
+ * will be returned.
+ */
+struct dc_stream_status *dc_stream_get_status_from_state(
+	struct dc_state *state,
 	struct dc_stream_state *stream)
 {
 	uint8_t i;
-	struct dc  *dc = stream->ctx->dc;
 
-	for (i = 0; i < dc->current_state->stream_count; i++) {
-		if (stream == dc->current_state->streams[i])
-			return &dc->current_state->stream_status[i];
+	for (i = 0; i < state->stream_count; i++) {
+		if (stream == state->streams[i])
+			return &state->stream_status[i];
 	}
 
 	return NULL;
 }
 
 /**
+ * dc_stream_get_status() - Get current stream status of the given stream state
+ * @stream: The stream to get the stream status for.
+ *
+ * The given stream is expected to exist in dc->current_state. Otherwise, NULL
+ * will be returned.
+ */
+struct dc_stream_status *dc_stream_get_status(
+	struct dc_stream_state *stream)
+{
+	struct dc *dc = stream->ctx->dc;
+	return dc_stream_get_status_from_state(dc->current_state, stream);
+}
+
+/**
  * dc_stream_set_cursor_attributes() - Update cursor attributes and set cursor surface address
  */
 bool dc_stream_set_cursor_attributes(
diff --git a/drivers/gpu/drm/amd/display/dc/dc_stream.h b/drivers/gpu/drm/amd/display/dc/dc_stream.h
index 1e1e89e..bfb741b 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_stream.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_stream.h
@@ -278,6 +278,9 @@ void update_stream_signal(struct dc_stream_state *stream, struct dc_sink *sink);
 void dc_stream_retain(struct dc_stream_state *dc_stream);
 void dc_stream_release(struct dc_stream_state *dc_stream);
 
+struct dc_stream_status *dc_stream_get_status_from_state(
+	struct dc_state *state,
+	struct dc_stream_state *stream);
 struct dc_stream_status *dc_stream_get_status(
 	struct dc_stream_state *dc_stream);
 
-- 
2.7.4