Provide test to verify the behavior of BACKGROUND_COLOR DRM CRTC
property.
This is achieved by filling a full-screen primary plane with a given
color and comparing the resulting CRC with the one obtained after
turning off all planes while having the CRTC background set to the same
color.
Also note this is a reworked version of the test that has been dropped
over 5 years ago via commit 33f07391e5f6 ("tests: Remove
kms_crtc_background_color test"), as the required kernel changes never
landed because of missing support in userland.
Signed-off-by: Cristian Ciocaltea <[email protected]>
---
This has been tested on both VKMS and the Rockchip RK3588 SoC based
Radxa ROCK 5B board. It relies on the kernel series [1] introducing the
BACKGROUND_COLOR CRTC property and a few additional patches from [2]
enabling the required CRC functionality for the Rockchip platform.
The patch adding support for setting custom background color in VKMS is
currently available at [3], but will be submitted soon as part of [1].
It's worth noting CRC is only supported by the display controller (VOP2)
present in the RK3576 SoC variant. However, the computation is done by
the hardware before applying the background color, hence it has limited
usage in IGT testing.
Luckily, the frame CRCs can be captured through DPCD, i.e. at
DisplayPort AUX channel level, hence I used the USB-C DP AltMode capable
port of the aforementioned board to perform the actual validation.
[1]
https://lore.kernel.org/all/[email protected]/
[2]
https://gitlab.collabora.com/hardware-enablement/rockchip-3588/linux/-/commits/cristicc/rk3588-vop2-crc
[3]
https://gitlab.collabora.com/hardware-enablement/rockchip-3588/linux/-/commits/cristicc/vkms-bgcolor
* Test results on VKMS
virtme-ng$ IGT_FORCE_DRIVER=vkms build/tests/kms_crtc_background_color
IGT-Version: 2.2-gf50583245 (x86_64) (Linux: 6.18.0-rc5-next-20251111+ x86_64)
Using IGT_SRANDOM=1763159189 for randomisation
Opened device: /dev/dri/card0
Starting subtest: background-color-red
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.071s)
Subtest background-color-red: SUCCESS (0.072s)
Starting subtest: background-color-green
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.072s)
Subtest background-color-green: SUCCESS (0.072s)
Starting subtest: background-color-blue
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.072s)
Subtest background-color-blue: SUCCESS (0.072s)
Starting subtest: background-color-yellow
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.073s)
Subtest background-color-yellow: SUCCESS (0.073s)
Starting subtest: background-color-purple
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.073s)
Subtest background-color-purple: SUCCESS (0.073s)
Starting subtest: background-color-cyan
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.073s)
Subtest background-color-cyan: SUCCESS (0.073s)
Starting subtest: background-color-black
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.073s)
Subtest background-color-black: SUCCESS (0.073s)
Starting subtest: background-color-white
Starting dynamic subtest: pipe-A-Virtual-1
Dynamic subtest pipe-A-Virtual-1: SUCCESS (0.072s)
Subtest background-color-white: SUCCESS (0.072s)
* Test results on ROCK5B
rock5b$ cat /sys/kernel/debug/dri/1/vop2/summary
Video Port0: DISABLED
Video Port1: DISABLED
Video Port2: ACTIVE
Connector: DP-1
bus_format[1018]: RGB101010_1X30
output_mode[f] color_space[0]
background color (10bpc): r=0x0 g=0x0 b=0x0
Display mode: 3840x2160p60
clk[594000] real_clk[594000] type[48] flag[9]
H: 3840 4016 4104 4400
V: 2160 2164 2174 2250
Cluster2-win0: ACTIVE
win_id: 2
format: XR24 little-endian (0x34325258) glb_alpha[0xff]
rotate: xmirror: 0 ymirror: 0 rotate_90: 0 rotate_270: 0
zpos: 0
src: pos[0, 0] rect[3840 x 2160]
dst: pos[0, 0] rect[3840 x 2160]
buf[0]: addr: 0x0000000000000000 pitch: 15360 offset: 0
rock5b$ build/tests/kms_crtc_background_color --device drm:/dev/dri/card1
IGT-Version: 2.2-g3e4ec308e (aarch64) (Linux: 6.18.0-rc1 aarch64)
Using IGT_SRANDOM=1762774806 for randomisation
Opened device: /dev/dri/card1
Starting subtest: background-color-red
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.491s)
Subtest background-color-red: SUCCESS (0.493s)
Starting subtest: background-color-green
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.533s)
Subtest background-color-green: SUCCESS (0.535s)
Starting subtest: background-color-blue
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.541s)
Subtest background-color-blue: SUCCESS (0.544s)
Starting subtest: background-color-yellow
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.535s)
Subtest background-color-yellow: SUCCESS (0.537s)
Starting subtest: background-color-purple
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.536s)
Subtest background-color-purple: SUCCESS (0.538s)
Starting subtest: background-color-cyan
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.539s)
Subtest background-color-cyan: SUCCESS (0.541s)
Starting subtest: background-color-black
Starting dynamic subtest: pipe-C-DP-1
(kms_crtc_background_color:744) igt_pipe_crc-WARNING: Warning on condition
all_zero in function crc_sanity_checks, file ../lib/igt_pipe_crc.c:475
(kms_crtc_background_color:744) igt_pipe_crc-WARNING: Suspicious CRC: All
values are 0.
(kms_crtc_background_color:744) igt_pipe_crc-WARNING: Warning on condition
all_zero in function crc_sanity_checks, file ../lib/igt_pipe_crc.c:475
(kms_crtc_background_color:744) igt_pipe_crc-WARNING: Suspicious CRC: All
values are 0.
Dynamic subtest pipe-C-DP-1: SUCCESS (0.535s)
Subtest background-color-black: SUCCESS (0.537s)
Starting subtest: background-color-white
Starting dynamic subtest: pipe-C-DP-1
Dynamic subtest pipe-C-DP-1: SUCCESS (0.540s)
Subtest background-color-white: SUCCESS (0.542s)
---
Changes in v2:
- Added VKMS test report
- Set the value of the CRTC background color property with 16bpc instead
of 8bpc, to avoid CRC check failures because of framebuffer format
precision mismatch - display controller drivers shall convert it back
from 16bpc to their internal representation of the pixel color if
necessary, e.g. VKMS already uses 16bpc, hence no conversion is
required in that case
- Replaced deprecated DRM_FORMAT_MOD_NONE with DRM_FORMAT_MOD_LINEAR
- Updated copyright section
- Link to v1:
https://lore.kernel.org/r/[email protected]
---
lib/igt_kms.c | 1 +
lib/igt_kms.h | 3 +-
tests/kms_crtc_background_color.c | 140 ++++++++++++++++++++++++++++++++++++++
tests/meson.build | 1 +
4 files changed, 144 insertions(+), 1 deletion(-)
diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 8973ffdb22a6..a6f547c04ce3 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -705,6 +705,7 @@ const char * const
igt_plane_prop_names[IGT_NUM_PLANE_PROPS] = {
};
const char * const igt_crtc_prop_names[IGT_NUM_CRTC_PROPS] = {
+ [IGT_CRTC_BACKGROUND] = "BACKGROUND_COLOR",
[IGT_CRTC_CTM] = "CTM",
[IGT_CRTC_GAMMA_LUT] = "GAMMA_LUT",
[IGT_CRTC_GAMMA_LUT_SIZE] = "GAMMA_LUT_SIZE",
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index f7ff0b17eb02..8e757a204197 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -156,7 +156,8 @@ void kmstest_restore_vt_mode(void);
void kmstest_set_vt_text_mode(void);
enum igt_atomic_crtc_properties {
- IGT_CRTC_CTM = 0,
+ IGT_CRTC_BACKGROUND = 0,
+ IGT_CRTC_CTM,
IGT_CRTC_GAMMA_LUT,
IGT_CRTC_GAMMA_LUT_SIZE,
IGT_CRTC_DEGAMMA_LUT,
diff --git a/tests/kms_crtc_background_color.c
b/tests/kms_crtc_background_color.c
new file mode 100644
index 000000000000..079c85ec55a2
--- /dev/null
+++ b/tests/kms_crtc_background_color.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2013,2014 Intel Corporation
+ * Copyright © 2025 Amazon.com, Inc. or its affiliates.
+ * Copyright © 2025 Collabora, Ltd.
+ */
+
+#include "igt.h"
+
+IGT_TEST_DESCRIPTION("Test crtc background color feature");
+
+typedef struct {
+ int drm_fd;
+ int debugfs;
+ igt_display_t display;
+} data_t;
+
+#define __DRM_ARGB64_PREP(c, shift) \
+ (((__u64)(c) & 0xffffU) << (shift))
+
+#define DRM_ARGB64_PREP(alpha, red, green, blue) \
+ (__DRM_ARGB64_PREP(alpha, 48) | \
+ __DRM_ARGB64_PREP(red, 32) | \
+ __DRM_ARGB64_PREP(green, 16) | \
+ __DRM_ARGB64_PREP(blue, 0))
+
+static void test_background(data_t *data, enum pipe pipe, igt_output_t *output,
+ __u16 red, __u16 green, __u16 blue)
+{
+ igt_display_t *display = &data->display;
+ igt_crc_t plane_crc, bg_crc;
+ igt_pipe_crc_t *pipe_crc;
+ igt_plane_t *plane;
+ drmModeModeInfo *mode;
+ struct igt_fb fb;
+
+ igt_display_reset(display);
+
+ igt_output_set_pipe(output, pipe);
+ mode = igt_output_get_mode(output);
+
+ plane = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
+
+ /* Fill the primary plane and set the background to the same color */
+ igt_create_color_fb(data->drm_fd,
+ mode->hdisplay, mode->vdisplay,
+ DRM_FORMAT_XRGB8888,
+ DRM_FORMAT_MOD_LINEAR,
+ (double)red / 0xffff,
+ (double)green / 0xffff,
+ (double)blue / 0xffff,
+ &fb);
+
+ igt_plane_set_fb(plane, &fb);
+ igt_pipe_set_prop_value(&data->display, pipe, IGT_CRTC_BACKGROUND,
+ DRM_ARGB64_PREP(0xffff, red, green, blue));
+ igt_display_commit2(&data->display, COMMIT_ATOMIC);
+
+ pipe_crc = igt_pipe_crc_new(data->drm_fd, pipe,
IGT_PIPE_CRC_SOURCE_AUTO);
+ igt_pipe_crc_collect_crc(pipe_crc, &plane_crc);
+
+ /* Turn off the primary plane so that only the background is visible */
+ igt_plane_set_fb(plane, NULL);
+ igt_display_commit2(&data->display, COMMIT_ATOMIC);
+ igt_pipe_crc_collect_crc(pipe_crc, &bg_crc);
+
+ /*
+ * The test assumes hardware is able to generate valid CRCs when setting
+ * the background color. Some platforms, e.g. Intel, might require at
+ * least one plane to be visible before reading the pipe-level ("dmux")
+ * CRC. Other platforms, e.g. Rockchip, do not take background color
+ * into account when computing CRC at CRTC level.
+ * A possible workaround would be to use alternative CRC sources, e.g.
+ * where computation is performed at encoder or sink level.
+ */
+ igt_assert_crc_equal(&plane_crc, &bg_crc);
+
+ /* Clean-up */
+ igt_pipe_set_prop_value(&data->display, pipe, IGT_CRTC_BACKGROUND,
+ DRM_ARGB64_PREP(0xffff, 0, 0, 0));
+ igt_pipe_crc_free(pipe_crc);
+ igt_output_set_pipe(output, PIPE_NONE);
+ igt_display_commit(display);
+ igt_remove_fb(data->drm_fd, &fb);
+}
+
+igt_main
+{
+ igt_output_t *output;
+ data_t data = {};
+ enum pipe pipe;
+ int i;
+
+ struct {
+ const char *color;
+ __u16 red;
+ __u16 green;
+ __u16 blue;
+ } tests[] = {
+ { "red", 0xffff, 0x0000, 0x0000, },
+ { "green", 0x0000, 0xffff, 0x0000, },
+ { "blue", 0x0000, 0x0000, 0xffff, },
+ { "yellow", 0xffff, 0xffff, 0x0000, },
+ { "purple", 0xffff, 0x0000, 0xffff, },
+ { "cyan", 0x0000, 0xffff, 0xffff, },
+ { "black", 0x0000, 0x0000, 0x0000, },
+ { "white", 0xffff, 0xffff, 0xffff, },
+ };
+
+ igt_fixture {
+ data.drm_fd = drm_open_driver_master(DRIVER_ANY);
+
+ kmstest_set_vt_graphics_mode();
+
+ igt_display_require(&data.display, data.drm_fd);
+ igt_display_require_output(&data.display);
+ igt_require_pipe_crc(data.drm_fd);
+
+ data.debugfs = igt_debugfs_dir(data.drm_fd);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(tests); i++) {
+ igt_describe_f("Test crtc background color %s", tests[i].color);
+ igt_subtest_with_dynamic_f("background-color-%s",
tests[i].color) {
+ for_each_pipe_with_single_output(&data.display, pipe,
output) {
+ igt_require(igt_pipe_has_prop(&data.display,
pipe,
+
IGT_CRTC_BACKGROUND));
+
+ igt_dynamic_f("pipe-%s-%s",
kmstest_pipe_name(pipe), output->name)
+ test_background(&data, pipe, output,
tests[i].red,
+ tests[i].green,
tests[i].blue);
+ }
+ }
+ }
+
+ igt_fixture {
+ igt_display_fini(&data.display);
+ drm_close_driver(data.drm_fd);
+ }
+}
diff --git a/tests/meson.build b/tests/meson.build
index ecc0f4c7f6f3..14067fd3d770 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -27,6 +27,7 @@ test_progs = [
'kms_color',
'kms_concurrent',
'kms_content_protection',
+ 'kms_crtc_background_color',
'kms_cursor_crc',
'kms_cursor_edge_walk',
'kms_cursor_legacy',
---
base-commit: 3813b62c3c6200f69d6cc8be1c5e621243ace24f
change-id: 20251110-crtc-bgcolor-f6ed9a58e0bf
