[igt-dev] [PATCH i-g-t] lib/igt_kms: Fix commits for planes with multiple possible CRTCs

* [igt-dev] [PATCH i-g-t] lib/igt_kms: Fix commits for planes with multiple possible CRTCs
@ 2019-02-21 21:23 Nicholas Kazlauskas
  2019-02-21 22:35 ` [igt-dev] ✓ Fi.CI.BAT: success for " Patchwork
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Nicholas Kazlauskas @ 2019-02-21 21:23 UTC (permalink / raw)
  To: igt-dev

An igt_plane_t is defined per igt_pipe_t. It is treated as its
own independent resource but DRM planes can be exposed to being used on
a number of possible CRTCs - making it a shared resource.

In IGT planes with multiple possible CRTCs are added to the plane list
for each pipe that the plane supports. The internal state remains
independent in IGT so when the same plane is modified for multiple
pipes in a single commit the last pipe to modify it is the one whose
state gets fully applied.

This situation happens fairly often in practice - resetting the display
at the start of the test before a commit will reset the CRTC ID and FB
ID for each plane.

For an example, consider the
igt@kms_plane_alpha_blend@pipe-a-constant-alpha-max test.

This test will fail for any overlay plane exposed for multiple CRTCs.

The test tries to set a framebuffer for pipe A but has all the other
pipes reset the plane state in the same commit. If there are multiple
pipes on the hardware then the last pipe will be the one to set all the
plane properties. The driver will receive a commit with no overlay
plane enabled since the last pipe set CRTC ID and FB ID to 0, disabling
the plane. The reference CRC capture will be incorrect since not all
the planes have been enabled and the subsequent CRC captures will
not match, failing the test.

The simplest (but hacky) fix to this problem is to only set the
properties for the plane for the pipe that last had it bound.

This patch introduces a global plane list on igt_display_t that keeps
track of the pipe that pipe that last called igt_plane_set_fb. The
properties for the plane will only be applied from that single pipe
when commiting the state to DRM.

No behavioral changes should be introduced by this patch for hardware
whose planes are only ever exposed one CRTC.

It would likely be best to eventually modify the igt_pipe_t plane list
to be a list of pointers to planes instead (igt_plane_t**)
instead of being the actual plane objects, but that can come later.

Many areas of the code like to make use of the backpointer to the pipe
on the plane which makes refactoring the code in that manner a little
trickier.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
---
 lib/igt_kms.c | 76 +++++++++++++++++++++++++++++++--------------------
 lib/igt_kms.h | 10 +++++++
 2 files changed, 57 insertions(+), 29 deletions(-)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 080f90ae..f133a5cd 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -1905,6 +1905,20 @@ void igt_display_require(igt_display_t *display, int drm_fd)
 	plane_resources = drmModeGetPlaneResources(display->drm_fd);
 	igt_assert(plane_resources);
 
+	display->n_planes = plane_resources->count_planes;
+	display->planes = calloc(sizeof(igt_plane_res_t), display->n_planes);
+	igt_assert_f(display->planes, "Failed to allocate memory for %d planes\n", display->n_planes);
+
+	for (i = 0; i < plane_resources->count_planes; ++i) {
+		igt_plane_res_t *plane = &display->planes[i];
+		uint32_t id = plane_resources->planes[i];
+
+		plane->drm_plane = drmModeGetPlane(display->drm_fd, id);
+		igt_assert(plane->drm_plane);
+
+		plane->type = get_drm_plane_type(display->drm_fd, id);
+	}
+
 	for_each_pipe(display, i) {
 		igt_pipe_t *pipe = &display->pipes[i];
 		igt_plane_t *plane;
@@ -1922,17 +1936,12 @@ void igt_display_require(igt_display_t *display, int drm_fd)
 		igt_fill_pipe_props(display, pipe, IGT_NUM_CRTC_PROPS, igt_crtc_prop_names);
 
 		/* count number of valid planes */
-		for (j = 0; j < plane_resources->count_planes; j++) {
-			drmModePlane *drm_plane;
-
-			drm_plane = drmModeGetPlane(display->drm_fd,
-						    plane_resources->planes[j]);
+		for (j = 0; j < display->n_planes; j++) {
+			drmModePlane *drm_plane = display->planes[j].drm_plane;
 			igt_assert(drm_plane);
 
 			if (drm_plane->possible_crtcs & (1 << i))
 				n_planes++;
-
-			drmModeFreePlane(drm_plane);
 		}
 
 		igt_assert_lt(0, n_planes);
@@ -1941,20 +1950,14 @@ void igt_display_require(igt_display_t *display, int drm_fd)
 		last_plane = n_planes - 1;
 
 		/* add the planes that can be used with that pipe */
-		for (j = 0; j < plane_resources->count_planes; j++) {
-			drmModePlane *drm_plane;
-
-			drm_plane = drmModeGetPlane(display->drm_fd,
-						    plane_resources->planes[j]);
-			igt_assert(drm_plane);
+		for (j = 0; j < display->n_planes; j++) {
+			igt_plane_res_t *res = &display->planes[j];
+			drmModePlane *drm_plane = res->drm_plane;
 
-			if (!(drm_plane->possible_crtcs & (1 << i))) {
-				drmModeFreePlane(drm_plane);
+			if (!(drm_plane->possible_crtcs & (1 << i)))
 				continue;
-			}
 
-			type = get_drm_plane_type(display->drm_fd,
-						  plane_resources->planes[j]);
+			type = res->type;
 
 			if (type == DRM_PLANE_TYPE_PRIMARY && pipe->plane_primary == -1) {
 				plane = &pipe->planes[0];
@@ -1975,6 +1978,10 @@ void igt_display_require(igt_display_t *display, int drm_fd)
 			plane->pipe = pipe;
 			plane->drm_plane = drm_plane;
 			plane->values[IGT_PLANE_IN_FENCE_FD] = ~0ULL;
+			plane->res = res;
+
+			if (!res->state)
+				res->state = plane;
 
 			igt_fill_plane_props(display, plane, IGT_NUM_PLANE_PROPS, igt_plane_prop_names);
 
@@ -2127,17 +2134,6 @@ igt_output_t *igt_output_from_connector(igt_display_t *display,
 
 static void igt_pipe_fini(igt_pipe_t *pipe)
 {
-	int i;
-
-	for (i = 0; i < pipe->n_planes; i++) {
-		igt_plane_t *plane = &pipe->planes[i];
-
-		if (plane->drm_plane) {
-			drmModeFreePlane(plane->drm_plane);
-			plane->drm_plane = NULL;
-		}
-	}
-
 	free(pipe->planes);
 	pipe->planes = NULL;
 
@@ -2163,6 +2159,15 @@ void igt_display_fini(igt_display_t *display)
 {
 	int i;
 
+	for (i = 0; i < display->n_planes; ++i) {
+		igt_plane_res_t *plane = &display->planes[i];
+
+		if (plane->drm_plane) {
+			drmModeFreePlane(plane->drm_plane);
+			plane->drm_plane = NULL;
+		}
+	}
+
 	for (i = 0; i < display->n_pipes; i++)
 		igt_pipe_fini(&display->pipes[i]);
 
@@ -2172,6 +2177,8 @@ void igt_display_fini(igt_display_t *display)
 	display->outputs = NULL;
 	free(display->pipes);
 	display->pipes = NULL;
+	free(display->planes);
+	display->planes = NULL;
 }
 
 static void igt_display_refresh(igt_display_t *display)
@@ -2789,6 +2796,10 @@ static int igt_pipe_commit(igt_pipe_t *pipe,
 	for (i = 0; i < pipe->n_planes; i++) {
 		igt_plane_t *plane = &pipe->planes[i];
 
+		/* skip planes that are handled by another pipe */
+		if (plane->res->state != plane)
+			continue;
+
 		ret = igt_plane_commit(plane, pipe, s, fail_on_error);
 		CHECK_RETURN(ret, fail_on_error);
 	}
@@ -3177,6 +3188,10 @@ static int igt_atomic_commit(igt_display_t *display, uint32_t flags, void *user_
 			igt_atomic_prepare_crtc_commit(pipe_obj, req);
 
 		for_each_plane_on_pipe(display, pipe, plane) {
+			/* skip planes that are handled by another pipe */
+			if (plane->res->state != plane)
+				continue;
+
 			if (plane->changed)
 				igt_atomic_prepare_plane_commit(plane, pipe_obj, req);
 		}
@@ -3709,6 +3724,9 @@ void igt_plane_set_fb(igt_plane_t *plane, struct igt_fb *fb)
 		if (igt_plane_has_prop(plane, IGT_PLANE_COLOR_RANGE))
 			igt_plane_set_prop_enum(plane, IGT_PLANE_COLOR_RANGE,
 				igt_color_range_to_str(fb->color_range));
+
+		/* hack to prioritize plane on crtc it was last bound to */
+		plane->res->state = plane;
 	} else {
 		igt_plane_set_size(plane, 0, 0);
 
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 679d4e84..32d840ce 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -285,6 +285,7 @@ extern const char * const igt_plane_prop_names[];
 
 typedef struct igt_display igt_display_t;
 typedef struct igt_pipe igt_pipe_t;
+typedef struct igt_plane_res igt_plane_res_t;
 typedef uint32_t igt_fixed_t;			/* 16.16 fixed point */
 
 typedef enum {
@@ -303,6 +304,7 @@ typedef enum {
 typedef struct {
 	/*< private >*/
 	igt_pipe_t *pipe;
+	igt_plane_res_t *res;
 	int index;
 	/* capabilities */
 	int type;
@@ -332,6 +334,12 @@ typedef struct {
 	int format_mod_count;
 } igt_plane_t;
 
+typedef struct igt_plane_res {
+	igt_plane_t *state;
+	drmModePlane *drm_plane;
+	int type;
+} igt_plane_res_t;
+
 struct igt_pipe {
 	igt_display_t *display;
 	enum pipe pipe;
@@ -372,8 +380,10 @@ struct igt_display {
 	int drm_fd;
 	int log_shift;
 	int n_pipes;
+	int n_planes;
 	int n_outputs;
 	igt_output_t *outputs;
+	igt_plane_res_t *planes;
 	igt_pipe_t *pipes;
 	bool has_cursor_plane;
 	bool is_atomic;
-- 
2.17.1

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