[PATCH i-g-t 1/2] tests/i915: Exercise coherency of mmapped frame buffers

Janusz Krzysztofik janusz.krzysztofik at linux.intel.com
Fri May 12 19:05:33 UTC 2023


Visible glitches have been observed when running graphics applications on
Linux under Xen hypervisor.  Those observations have been confirmed with
failures from kms_pwrite_crc Intel GPU test that verifies data coherency
of DRM frame buffer objects using hardware CRC checksums calculated by
display controllers, exposed to userspace via debugfs.

Since not all applications were affected, we need to use more methods than
just pwrite in order to identify affected processing paths.  Create a new
test focused on exercising coherency of future scanout buffers populated
over mmap.  Cover all available mmap methods and caching modes.

Link: https://gitlab.freedesktop.org/drm/intel/-/issues/7648
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
---
 tests/i915/kms_fb_coherency.c | 365 ++++++++++++++++++++++++++++++++++
 tests/meson.build             |   1 +
 2 files changed, 366 insertions(+)
 create mode 100644 tests/i915/kms_fb_coherency.c

diff --git a/tests/i915/kms_fb_coherency.c b/tests/i915/kms_fb_coherency.c
new file mode 100644
index 0000000000..41da26cf27
--- /dev/null
+++ b/tests/i915/kms_fb_coherency.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ *
+ * Derived from tests/i915/kms_pwrite_crc.c
+ * Copyright © 2014 Intel Corporation
+ */
+
+/**
+ * TEST: kms_fb_coherency
+ * Description: Exercise coherency of future scanout buffer objects
+ */
+
+#include "igt.h"
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+
+typedef struct {
+	int drm_fd;
+	igt_display_t display;
+	struct igt_fb fb[2];
+	igt_output_t *output;
+	igt_plane_t *primary;
+	enum pipe pipe;
+	igt_crc_t ref_crc;
+	igt_pipe_crc_t *pipe_crc;
+	uint32_t devid;
+} data_t;
+
+static void prepare_crtc(data_t *data)
+{
+	igt_display_t *display = &data->display;
+	igt_output_t *output = data->output;
+	drmModeModeInfo *mode;
+
+	igt_display_reset(display);
+	/* select the pipe we want to use */
+	igt_output_set_pipe(output, data->pipe);
+
+	mode = igt_output_get_mode(output);
+
+	/* create a white reference fb and flip to it */
+	igt_create_color_fb(data->drm_fd, mode->hdisplay, mode->vdisplay,
+			    DRM_FORMAT_XRGB8888, DRM_FORMAT_MOD_LINEAR,
+			    1.0, 1.0, 1.0, &data->fb[0]);
+
+	data->primary = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
+
+	igt_plane_set_fb(data->primary, &data->fb[0]);
+	igt_display_commit(display);
+
+	if (data->pipe_crc)
+		igt_pipe_crc_free(data->pipe_crc);
+
+	data->pipe_crc = igt_pipe_crc_new(data->drm_fd, data->pipe,
+					  IGT_PIPE_CRC_SOURCE_AUTO);
+
+	/* get reference crc for the white fb */
+	igt_pipe_crc_collect_crc(data->pipe_crc, &data->ref_crc);
+}
+
+static struct igt_fb *prepare_fb(data_t *data)
+{
+	igt_output_t *output = data->output;
+	struct igt_fb *fb = &data->fb[1];
+	drmModeModeInfo *mode;
+
+	prepare_crtc(data);
+
+	mode = igt_output_get_mode(output);
+
+	/* create a non-white fb we can overwrite later */
+	igt_create_pattern_fb(data->drm_fd, mode->hdisplay, mode->vdisplay,
+			      DRM_FORMAT_XRGB8888, DRM_FORMAT_MOD_LINEAR, fb);
+
+	/* flip to it to make it UC/WC and fully flushed */
+	drmModeSetPlane(data->drm_fd,
+			data->primary->drm_plane->plane_id,
+			output->config.crtc->crtc_id,
+			fb->fb_id, 0,
+			0, 0, fb->width, fb->height,
+			0, 0, fb->width << 16, fb->height << 16);
+
+	/* flip back the original white buffer */
+	drmModeSetPlane(data->drm_fd,
+			data->primary->drm_plane->plane_id,
+			output->config.crtc->crtc_id,
+			data->fb[0].fb_id, 0,
+			0, 0, fb->width, fb->height,
+			0, 0, fb->width << 16, fb->height << 16);
+
+	if (!gem_has_lmem(data->drm_fd)) {
+		uint32_t caching;
+
+		/* make sure caching mode has become UC/WT */
+		caching = gem_get_caching(data->drm_fd, fb->gem_handle);
+		igt_assert(caching == I915_CACHING_NONE ||
+			   caching == I915_CACHING_DISPLAY);
+	}
+
+	return fb;
+}
+
+static igt_crc_t get_buf_crc(data_t *data, void *buf, igt_fb_t *fb)
+{
+	igt_crc_t crc;
+
+	/* use memset to make the mmapped fb all white */
+	memset(buf, 0xff, fb->size);
+	munmap(buf, fb->size);
+
+	/* and flip to it */
+	drmModeSetPlane(data->drm_fd,
+			data->primary->drm_plane->plane_id,
+			data->output->config.crtc->crtc_id,
+			fb->fb_id, 0,
+			0, 0, fb->width, fb->height,
+			0, 0, fb->width << 16, fb->height << 16);
+
+	/* check that the crc is as expected, which requires that caches got flushed */
+	igt_pipe_crc_collect_crc(data->pipe_crc, &crc);
+	return crc;
+}
+
+static void cleanup_crtc(data_t *data)
+{
+	igt_display_t *display = &data->display;
+	igt_output_t *output = data->output;
+
+	igt_pipe_crc_free(data->pipe_crc);
+	data->pipe_crc = NULL;
+
+	igt_plane_set_fb(data->primary, NULL);
+
+	igt_output_set_pipe(output, PIPE_ANY);
+	igt_display_commit(display);
+
+	igt_remove_fb(data->drm_fd, &data->fb[0]);
+	igt_remove_fb(data->drm_fd, &data->fb[1]);
+
+}
+
+static void test_mmap_gtt(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	gem_require_mappable_ggtt(data->drm_fd);
+
+	fb = prepare_fb(data);
+
+	buf = gem_mmap__gtt(data->drm_fd, fb->gem_handle, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_assert_crc_equal(&crc, &data->ref_crc);
+}
+
+static void test_mmap_offset_wc(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_mmap_offset__has_wc(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	buf = gem_mmap_offset__wc(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_assert_crc_equal(&crc, &data->ref_crc);
+}
+
+static void test_mmap_offset_wb(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_has_mmap_offset(data->drm_fd));
+	igt_skip_on(gem_has_lmem(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	/* mmap the fb */
+	buf = gem_mmap_offset__cpu(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_fail_on(igt_check_crc_equal(&crc, &data->ref_crc));
+}
+
+static void test_mmap_offset_uc(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_has_mmap_offset(data->drm_fd));
+	igt_skip_on(gem_has_lmem(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	/* mmap the fb */
+	buf = __gem_mmap_offset(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE,
+				I915_MMAP_OFFSET_UC);
+	igt_assert(buf);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_assert_crc_equal(&crc, &data->ref_crc);
+}
+
+static void test_mmap_offset_fixed(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_has_lmem(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	/* mmap the fb */
+	buf = gem_mmap_offset__fixed(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_assert_crc_equal(&crc, &data->ref_crc);
+}
+
+static void test_legacy_mmap_wc(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_has_legacy_mmap(data->drm_fd));
+	igt_require(gem_mmap__has_wc(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	/* mmap the fb */
+	buf = gem_mmap__wc(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_assert_crc_equal(&crc, &data->ref_crc);
+}
+
+static void test_legacy_mmap_cpu(data_t *data)
+{
+	igt_crc_t crc;
+	igt_fb_t *fb;
+	void *buf;
+
+	igt_require(gem_has_legacy_mmap(data->drm_fd));
+
+	fb = prepare_fb(data);
+
+	/* mmap the fb */
+	buf = gem_mmap__cpu(data->drm_fd, fb->gem_handle, 0, fb->size, PROT_WRITE);
+
+	crc = get_buf_crc(data, buf, fb);
+	igt_fail_on(igt_check_crc_equal(&crc, &data->ref_crc));
+}
+
+static void select_valid_pipe_output_combo(data_t *data)
+{
+	igt_display_t *display = &data->display;
+
+	for_each_pipe_with_valid_output(display, data->pipe, data->output) {
+		igt_display_reset(display);
+
+		igt_output_set_pipe(data->output, data->pipe);
+		if (!i915_pipe_output_combo_valid(display))
+			continue;
+
+		/* one is enough */
+		return;
+	}
+
+	igt_skip("no valid crtc/connector combinations found\n");
+}
+
+igt_main
+{
+	data_t data;
+
+	igt_fixture {
+		data.drm_fd = drm_open_driver_master(DRIVER_INTEL);
+
+		data.devid = intel_get_drm_devid(data.drm_fd);
+
+		kmstest_set_vt_graphics_mode();
+
+		igt_require_pipe_crc(data.drm_fd);
+
+		igt_display_require(&data.display, data.drm_fd);
+
+		select_valid_pipe_output_combo(&data);
+	}
+
+	/**
+	 * SUBTEST: memset-crc
+	 * Description: Use display controller CRC hardware to validate (non)coherency
+	 *		of memset operations on future scanout buffer objects
+	 *		mmapped with different mmap methods and different caching modes.
+	 */
+	igt_subtest_with_dynamic("memset-crc") {
+		if (gem_has_mappable_ggtt(data.drm_fd)) {
+			igt_dynamic("mmap-gtt")
+				test_mmap_gtt(&data);
+
+			cleanup_crtc(&data);
+		}
+
+		if (gem_mmap_offset__has_wc(data.drm_fd)) {
+			igt_dynamic("mmap-offset-wc")
+				test_mmap_offset_wc(&data);
+
+			cleanup_crtc(&data);
+		}
+
+		if (gem_has_mmap_offset(data.drm_fd)) {
+			if (gem_has_lmem(data.drm_fd)) {
+				igt_dynamic("mmap-offset-fixed")
+					test_mmap_offset_fixed(&data);
+
+				cleanup_crtc(&data);
+
+			} else {
+				igt_dynamic("mmap-offset-wb")
+					test_mmap_offset_wb(&data);
+
+				cleanup_crtc(&data);
+
+				igt_dynamic("mmap-offset-uc")
+					test_mmap_offset_uc(&data);
+
+				cleanup_crtc(&data);
+			}
+		}
+
+		if (gem_has_legacy_mmap(data.drm_fd)) {
+			if (gem_mmap__has_wc(data.drm_fd)) {
+				igt_dynamic("mmap-offset-wc")
+					test_legacy_mmap_wc(&data);
+
+				cleanup_crtc(&data);
+			}
+
+			igt_dynamic("mmap-offset-wc")
+				test_legacy_mmap_cpu(&data);
+
+			cleanup_crtc(&data);
+		}
+	}
+
+	igt_fixture {
+		igt_display_fini(&data.display);
+		close(data.drm_fd);
+	}
+}
diff --git a/tests/meson.build b/tests/meson.build
index c15eb3a08c..371b501992 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -224,6 +224,7 @@ i915_progs = [
 	'kms_ccs',
 	'kms_cdclk',
 	'kms_draw_crc',
+	'kms_fb_coherency',
 	'kms_fbcon_fbt',
 	'kms_fence_pin_leak',
 	'kms_flip_scaled_crc',
-- 
2.40.1



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