[igt-dev] [PATCH] tests/kms_dither: New IGT to validate crtc Dithering

Bhanuprakash Modem bhanuprakash.modem at intel.com
Sun Jul 26 12:29:44 UTC 2020


Many of the display devices have color format support less than
the color format of the input data (Ex: 8-bit input data and 6-bit
display color depth). Then the input data will be either truncated
or rounded, but this approach usually causes loss of detail and also
produce large banded areas of a single color that significantly
differs from the original image.

Dithering is a technique used to enhance these colors by creating the
illusion of smoothness by adjusting the nearby pixel color.
For Eg: Converting 8-bit to 6-bit by modifying the pixel information.

Dithering should be enabled when a panel color depth is lower than the
color depth of the framebuffer.

Even though feature Dithering is there since legacy, there is no
specific IGT for this. This patch will create New IGT for Dithering.
And below is the truth table for CRTC Dithering.

|----------------|---------|-------------|
|  Frame buffer  |  Panel  |  Dithering  |
|----------------|---------|-------------|
|      8 BPC     |  6 BPC  |     Yes     |
|----------------|---------|-------------|
|      8 BPC     |  8 BPC  |     No      |
|----------------|---------|-------------|
|      8 BPC     | 10 BPC  |     No      |
|----------------|---------|-------------|
|     10 BPC     |  6 BPC  |     Yes     |
|----------------|---------|-------------|
|     10 BPC     |  8 BPC  |     Yes     |
|----------------|---------|-------------|
|     10 BPC     | 10 BPC  |     No      |
|----------------|---------|-------------|
|     16 BPC     |  6 BPC  |     Yes     |
|----------------|---------|-------------|
|     16 BPC     |  8 BPC  |     Yes     |
|----------------|---------|-------------|
|     16 BPC     | 10 BPC  |     Yes     |
|----------------|---------|-------------|

v2:
* Fix commit message (Karthik)
* Add file author (Karthik)
* Dynamic subtests for pipe-output combinations (Karthik)
* Update deprecated pipe name (Karthik)
* Remove redundant fb creation logic (Karthik)

v3:
* Use for_each_pipe_with_valid_output() to simplify the logic (Bhanu)
* Remove magic numbers to create fb (Karthik)
* Fix typos & comments (Swati)

v4:
* Remove explicit igt_require for a valid output found,
  igt_subtest_with_dynamic will handle the SKIP (Petri)
* Limit the execution to a single pipe (Uma)

Cc: Swati Sharma <swati2.sharma at intel.com>
Cc: Karthik B S <karthik.b.s at intel.com>
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya at intel.com>
Cc: Petri Latvala <petri.latvala at intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
 tests/Makefile.sources |   1 +
 tests/kms_dither.c     | 249 +++++++++++++++++++++++++++++++++++++++++
 tests/meson.build      |   1 +
 3 files changed, 251 insertions(+)
 create mode 100644 tests/kms_dither.c

diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index 93d7768c..f22b3f33 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -44,6 +44,7 @@ TESTS_progs = \
 	kms_cursor_crc \
 	kms_cursor_edge_walk \
 	kms_cursor_legacy \
+	kms_dither \
 	kms_dp_aux_dev \
 	kms_dp_dsc \
 	kms_dp_tiled_display \
diff --git a/tests/kms_dither.c b/tests/kms_dither.c
new file mode 100644
index 00000000..dd62f21c
--- /dev/null
+++ b/tests/kms_dither.c
@@ -0,0 +1,249 @@
+/*
+ * Copyright © 2020 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *     Bhanuprakash Modem <bhanuprakash.modem at intel.com>
+ *
+ */
+
+#include "igt.h"
+#include <fcntl.h>
+#include <termios.h>
+#include <unistd.h>
+
+IGT_TEST_DESCRIPTION("Test Dithering block status");
+
+/* Connector BPC */
+#define IGT_CONNECTOR_BPC_6		6
+#define IGT_CONNECTOR_BPC_8		8
+#define IGT_CONNECTOR_BPC_10		10
+#define IGT_CONNECTOR_BPC_12		12
+
+/* Framebuffer BPC */
+#define IGT_FRAME_BUFFER_BPC_8		8
+#define IGT_FRAME_BUFFER_BPC_10		10
+#define IGT_FRAME_BUFFER_BPC_16		16
+
+/* Test flags. */
+enum {
+	TEST_NONE = 1 << 0,
+	TEST_SUSPEND = 1 << 1,
+};
+
+/* Common test data. */
+typedef struct data {
+	igt_display_t display;
+	igt_plane_t *primary;
+	igt_output_t *output;
+	igt_pipe_t *pipe;
+	drmModeModeInfo *mode;
+	enum pipe pipe_id;
+	int drm_fd;
+	igt_fb_t fb;
+} data_t;
+
+/* Prepare test data. */
+static void prepare_test(data_t *data, igt_output_t *output, enum pipe pipe)
+{
+	igt_display_t *display = &data->display;
+
+	data->pipe_id = pipe;
+	data->pipe = &data->display.pipes[data->pipe_id];
+	igt_assert(data->pipe);
+
+	igt_display_reset(display);
+
+	data->output = output;
+	igt_assert(data->output);
+
+	data->mode = igt_output_get_mode(data->output);
+	igt_assert(data->mode);
+
+	data->primary =
+		igt_pipe_get_plane_type(data->pipe, DRM_PLANE_TYPE_PRIMARY);
+
+	igt_output_set_pipe(data->output, data->pipe_id);
+}
+
+/* Returns the current state of dithering from the crtc debugfs. */
+static bool get_dither_state(data_t *data)
+{
+	char buf[256];
+	char crtc_name[7];
+	char *start_loc;
+	int fd, res;
+	unsigned int status;
+
+	snprintf(crtc_name, 7, "crtc-%d", data->pipe_id);
+	fd = igt_debugfs_open(data->drm_fd, crtc_name, O_RDONLY);
+	igt_assert(fd >= 0);
+
+	res = igt_debugfs_simple_read(fd, "dither", buf, sizeof(buf));
+	igt_require(res > 0);
+	close(fd);
+
+	igt_assert(start_loc = strstr(buf, "Dither: "));
+	igt_assert_eq(sscanf(start_loc, "Dither: %u", &status), 1);
+
+	return !!status;
+}
+
+/* Returns the maximum bpc from the connector debugfs. */
+static unsigned int get_output_bpc(data_t *data, igt_output_t *output)
+{
+	char buf[256];
+	char *start_loc;
+	int fd, res;
+	unsigned int max_bpc;
+
+	fd = igt_debugfs_connector_dir(data->drm_fd, output->name, O_RDONLY);
+	igt_assert(fd >= 0);
+
+	res = igt_debugfs_simple_read(fd, "output_bpc", buf, sizeof(buf));
+	igt_require(res > 0);
+	close(fd);
+
+	igt_assert(start_loc = strstr(buf, "Maximum: "));
+	igt_assert_eq(sscanf(start_loc, "Maximum: %u", &max_bpc), 1);
+
+	return max_bpc;
+}
+
+static void test_dithering(data_t *data, enum pipe pipe,
+			   igt_output_t *output,
+			   int fb_bpc, int fb_format,
+			   int output_bpc, uint32_t flags)
+{
+	igt_display_t *display = &data->display;
+	bool enabled;
+
+	igt_info("Dithering test execution on %s PIPE_%s\n",
+			output->name, kmstest_pipe_name(pipe));
+	prepare_test(data, output, pipe);
+
+	igt_assert(igt_create_fb(data->drm_fd, data->mode->hdisplay,
+				 data->mode->vdisplay, fb_format,
+				 LOCAL_DRM_FORMAT_MOD_NONE, &data->fb));
+	igt_plane_set_fb(data->primary, &data->fb);
+	igt_plane_set_size(data->primary, data->mode->hdisplay, data->mode->vdisplay);
+	igt_output_set_prop_value(data->output, IGT_CONNECTOR_MAX_BPC, output_bpc);
+	igt_display_commit2(display, display->is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
+
+	/*
+	 * Check the status of Dithering block:
+	 * If fb_bpc is greater than output_bpc, Dithering should be enabled
+	 * Else disabled
+	 */
+	enabled = get_dither_state(data);
+	if (fb_bpc > output_bpc)
+		igt_assert_f(enabled, "(fb_%dbpc > output_%dbpc): Dither should be enabled\n",
+				fb_bpc, output_bpc);
+	else
+		igt_assert_f(!enabled, "(fb_%dbpc <= output_%dbpc): Dither should be disabled\n",
+				fb_bpc, output_bpc);
+
+	igt_plane_set_fb(data->primary, NULL);
+	igt_output_set_pipe(output, PIPE_NONE);
+	igt_display_commit2(display, display->is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
+
+	igt_remove_fb(data->drm_fd, &data->fb);
+
+	return;
+}
+
+/* Returns true if an output supports max bpc property. */
+static bool has_max_bpc(igt_output_t *output)
+{
+        return igt_output_has_prop(output, IGT_CONNECTOR_MAX_BPC) &&
+               igt_output_get_prop(output, IGT_CONNECTOR_MAX_BPC);
+}
+
+static void
+run_dither_test(data_t *data, int fb_bpc, int fb_format, int output_bpc,
+		uint32_t flags)
+{
+	igt_output_t *output;
+	igt_display_t *display = &data->display;
+	enum pipe pipe;
+
+	for_each_pipe_with_valid_output(display, pipe, output) {
+		if (!has_max_bpc(output))
+			continue;
+
+		if (get_output_bpc(data, output) < output_bpc)
+			continue;
+
+		igt_dynamic_f("%s-pipe-%s", output->name, kmstest_pipe_name(pipe))
+			if (igt_pipe_connector_valid(pipe, output))
+				test_dithering(data, pipe, output, fb_bpc,
+					       fb_format, output_bpc, flags);
+
+		/* One is enough */
+		return;
+	}
+}
+
+igt_main
+{
+	struct {
+		int bpc;
+		int format;
+	} fb_formats[] = {
+		{ IGT_FRAME_BUFFER_BPC_8, DRM_FORMAT_RGB888 },
+		{ IGT_FRAME_BUFFER_BPC_10, DRM_FORMAT_XRGB2101010 },
+		{ IGT_FRAME_BUFFER_BPC_16, DRM_FORMAT_XRGB16161616F },
+	};
+	int output_bpc[] = {
+		IGT_CONNECTOR_BPC_6,
+		IGT_CONNECTOR_BPC_8,
+		IGT_CONNECTOR_BPC_10
+	};
+	int i, j;
+	data_t data = { 0 };
+
+	igt_fixture {
+		data.drm_fd = drm_open_driver_master(DRIVER_INTEL);
+		kmstest_set_vt_graphics_mode();
+
+		igt_display_require(&data.display, data.drm_fd);
+		igt_display_require_output(&data.display);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(fb_formats); i++) {
+		for (j = 0; j < ARRAY_SIZE(output_bpc); j++) {
+			igt_describe_f("Framebuffer BPC:%d, Panel BPC:%d, Expected Dither:%s\n",
+				       fb_formats[i].bpc, output_bpc[j],
+				       (fb_formats[i].bpc > output_bpc[j]) ? "Enable": "Disable");
+
+			igt_subtest_with_dynamic_f("FB-%dBPC-Vs-Panel-%dBPC", fb_formats[i].bpc, output_bpc[j])
+				run_dither_test(&data,
+						fb_formats[i].bpc,
+						fb_formats[i].format,
+						output_bpc[j],
+						TEST_NONE);
+		}
+	}
+
+	igt_fixture {
+		igt_display_fini(&data.display);
+	}
+}
diff --git a/tests/meson.build b/tests/meson.build
index ca792ed8..e50ff7e4 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -28,6 +28,7 @@ test_progs = [
 	'kms_cursor_crc',
 	'kms_cursor_edge_walk',
 	'kms_cursor_legacy',
+	'kms_dither',
 	'kms_dp_aux_dev',
 	'kms_dp_dsc',
 	'kms_dp_tiled_display',
-- 
2.20.1



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