[igt-dev] [PATCH i-g-t v8 1/4] lib/igt_kms: Add writeback support

[Rodrigo Siqueira]

From: Brian Starkey <rodrigosiqueiramelo at gmail.com>

Add support in igt_kms for writeback connectors, with the ability
to attach framebuffers.

v5: Rebase and add DRM_CLIENT_CAP_WRITEBACK_CONNECTORS before
drmModeGetResources()

Signed-off-by: Brian Starkey <brian.starkey at arm.com>
[rebased and updated to the latest igt style]
Signed-off-by: Liviu Dudau <liviu.dudau at arm.com>
[rebased and updated to the latest igt style]
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
Reviewed-by: Liviu Dudau <liviu.dudau at arm.com>
Reviewed-by: Simon Ser <simon.ser at intel.com>
---
 lib/igt_kms.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |  6 ++++++
 2 files changed, 63 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index e9621e7e..67053d8b 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -421,6 +421,9 @@ const char * const igt_connector_prop_names[IGT_NUM_CONNECTOR_PROPS] = {
 	[IGT_CONNECTOR_LINK_STATUS] = "link-status",
 	[IGT_CONNECTOR_MAX_BPC] = "max bpc",
 	[IGT_CONNECTOR_HDR_OUTPUT_METADATA] = "HDR_OUTPUT_METADATA",
+	[IGT_CONNECTOR_WRITEBACK_PIXEL_FORMATS] = "WRITEBACK_PIXEL_FORMATS",
+	[IGT_CONNECTOR_WRITEBACK_FB_ID] = "WRITEBACK_FB_ID",
+	[IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR] = "WRITEBACK_OUT_FENCE_PTR",
 };
 
 /*
@@ -653,6 +656,7 @@ static const struct type_name connector_type_names[] = {
 	{ DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
 	{ DRM_MODE_CONNECTOR_DSI, "DSI" },
 	{ DRM_MODE_CONNECTOR_DPI, "DPI" },
+	{ DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" },
 	{}
 };
 
@@ -1802,6 +1806,14 @@ static void igt_output_reset(igt_output_t *output)
 	if (igt_output_has_prop(output, IGT_CONNECTOR_HDR_OUTPUT_METADATA))
 		igt_output_set_prop_value(output,
 					  IGT_CONNECTOR_HDR_OUTPUT_METADATA, 0);
+
+	if (igt_output_has_prop(output, IGT_CONNECTOR_WRITEBACK_FB_ID))
+		igt_output_set_prop_value(output, IGT_CONNECTOR_WRITEBACK_FB_ID, 0);
+	if (igt_output_has_prop(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR)) {
+		igt_output_clear_prop_changed(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR);
+		output->writeback_out_fence_fd = -1;
+	}
+
 }
 
 /**
@@ -1885,6 +1897,8 @@ void igt_display_require(igt_display_t *display, int drm_fd)
 
 	display->drm_fd = drm_fd;
 
+	drmSetClientCap(drm_fd, DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1);
+
 	resources = drmModeGetResources(display->drm_fd);
 	if (!resources)
 		goto out;
@@ -2193,6 +2207,11 @@ static void igt_output_fini(igt_output_t *output)
 	kmstest_free_connector_config(&output->config);
 	free(output->name);
 	output->name = NULL;
+
+	if (output->writeback_out_fence_fd != -1) {
+		close(output->writeback_out_fence_fd);
+		output->writeback_out_fence_fd = -1;
+	}
 }
 
 /**
@@ -3255,6 +3274,11 @@ static void igt_atomic_prepare_connector_commit(igt_output_t *output, drmModeAto
 					  output->props[i],
 					  output->values[i]));
 	}
+
+	if (output->writeback_out_fence_fd != -1) {
+		close(output->writeback_out_fence_fd);
+		output->writeback_out_fence_fd = -1;
+	}
 }
 
 /*
@@ -3377,6 +3401,16 @@ display_commit_changed(igt_display_t *display, enum igt_commit_style s)
 		else
 			/* no modeset in universal commit, no change to crtc. */
 			output->changed &= 1 << IGT_CONNECTOR_CRTC_ID;
+
+		if (s == COMMIT_ATOMIC) {
+			if (igt_output_is_prop_changed(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR))
+				igt_assert(output->writeback_out_fence_fd >= 0);
+
+			output->values[IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR] = 0;
+			output->values[IGT_CONNECTOR_WRITEBACK_FB_ID] = 0;
+			igt_output_clear_prop_changed(output, IGT_CONNECTOR_WRITEBACK_FB_ID);
+			igt_output_clear_prop_changed(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR);
+		}
 	}
 
 	if (display->first_commit) {
@@ -4049,6 +4083,29 @@ void igt_pipe_request_out_fence(igt_pipe_t *pipe)
 	igt_pipe_obj_set_prop_value(pipe, IGT_CRTC_OUT_FENCE_PTR, (ptrdiff_t)&pipe->out_fence_fd);
 }
 
+/**
+ * igt_output_set_writeback_fb:
+ * @output: Target output
+ * @fb: Target framebuffer
+ *
+ * This function sets the given @fb to be used as the target framebuffer for the
+ * writeback engine at the next atomic commit. It will also request a writeback
+ * out fence that will contain the fd number of the out fence created by KMS if
+ * the given @fb is valid.
+ */
+void igt_output_set_writeback_fb(igt_output_t *output, struct igt_fb *fb)
+{
+	igt_display_t *display = output->display;
+
+	LOG(display, "%s: output_set_writeback_fb(%d)\n", output->name, fb ? fb->fb_id : 0);
+
+	igt_output_set_prop_value(output, IGT_CONNECTOR_WRITEBACK_FB_ID, fb ? fb->fb_id : 0);
+	/* only request a writeback out fence if the framebuffer is valid */
+	if (fb)
+		igt_output_set_prop_value(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR,
+					  (ptrdiff_t)&output->writeback_out_fence_fd);
+}
+
 /**
  * igt_wait_for_vblank_count:
  * @drm_fd: A drm file descriptor
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index adca59ac..aa082ef6 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -127,6 +127,9 @@ enum igt_atomic_connector_properties {
        IGT_CONNECTOR_LINK_STATUS,
        IGT_CONNECTOR_MAX_BPC,
        IGT_CONNECTOR_HDR_OUTPUT_METADATA,
+       IGT_CONNECTOR_WRITEBACK_PIXEL_FORMATS,
+       IGT_CONNECTOR_WRITEBACK_FB_ID,
+       IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR,
        IGT_NUM_CONNECTOR_PROPS
 };
 
@@ -366,6 +369,8 @@ typedef struct {
 	bool use_override_mode;
 	drmModeModeInfo override_mode;
 
+	int32_t writeback_out_fence_fd;
+
 	/* bitmask of changed properties */
 	uint64_t changed;
 
@@ -425,6 +430,7 @@ igt_output_t *igt_output_from_connector(igt_display_t *display,
     drmModeConnector *connector);
 void igt_output_refresh(igt_output_t *output);
 const drmModeModeInfo *igt_std_1024_mode_get(void);
+void igt_output_set_writeback_fb(igt_output_t *output, struct igt_fb *fb);
 
 igt_plane_t *igt_pipe_get_plane_type(igt_pipe_t *pipe, int plane_type);
 int igt_pipe_count_plane_type(igt_pipe_t *pipe, int plane_type);
-- 
2.26.0