Re: [igt-dev] [PATCH V6 i-g-t 2/6] kms_writeback: Add initial writeback tests

Ser, Simon
2019-07-10T11:57:30Z

Hi,

Thanks for the patch! Here are a few comments.

For bonus points, it would be nice to add igt_describe descriptions of
each sub-test.

On Wed, 2019-06-12 at 23:16 -0300, Brian Starkey wrote:
> Add tests for the WRITEBACK_PIXEL_FORMATS, WRITEBACK_OUT_FENCE_PTR and
> WRITEBACK_FB_ID properties on writeback connectors, ensuring their
> behaviour is correct.
>
> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
> [rebased and updated do_writeback_test() function to address feedback]
> Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
> ---
> tests/Makefile.sources | 1 +
> tests/kms_writeback.c | 314 +++++++++++++++++++++++++++++++++++++++++
> tests/meson.build | 1 +
> 3 files changed, 316 insertions(+)
> create mode 100644 tests/kms_writeback.c
>
> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
> index 027ed82f..03cc8efa 100644
> --- a/tests/Makefile.sources
> +++ b/tests/Makefile.sources
> @@ -77,6 +77,7 @@ TESTS_progs = \
> kms_universal_plane \
> kms_vblank \
> kms_vrr \
> + kms_writeback \
> meta_test \
> perf \
> perf_pmu \
> diff --git a/tests/kms_writeback.c b/tests/kms_writeback.c
> new file mode 100644
> index 00000000..66ef48a6
> --- /dev/null
> +++ b/tests/kms_writeback.c
> @@ -0,0 +1,314 @@
> +/*
> + * (C) COPYRIGHT 2017 ARM Limited. All rights reserved.
> + *
> + * 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 AUTHORS OR COPYRIGHT HOLDERS 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.
> + *
> + */
> +
> +#include <errno.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include "igt.h"
> +#include "igt_core.h"
> +#include "igt_fb.h"
> +
> +static drmModePropertyBlobRes *get_writeback_formats_blob(igt_output_t *output)
> +{
> + drmModePropertyBlobRes *blob = NULL;
> + uint64_t blob_id;
> + int ret;
> +
> + ret = kmstest_get_property(output->display->drm_fd,
> + output->config.connector->connector_id,
> + DRM_MODE_OBJECT_CONNECTOR,
> + igt_connector_prop_names[IGT_CONNECTOR_WRITEBACK_PIXEL_FORMATS],
> + NULL, &blob_id, NULL);
> + if (ret)
> + blob = drmModeGetPropertyBlob(output->display->drm_fd, blob_id);
> +
> + igt_assert(blob);
> +
> + return blob;
> +}
> +
> +static bool check_writeback_config(igt_display_t *display, igt_output_t *output)
> +{
> + igt_fb_t input_fb, output_fb;
> + igt_plane_t *plane;
> + uint32_t writeback_format = DRM_FORMAT_XRGB8888;
> + uint64_t tiling = igt_fb_mod_to_tiling(0);
> + int width, height, ret;
> + drmModeModeInfo override_mode = {
> + .clock = 25175,
> + .hdisplay = 640,
> + .hsync_start = 656,
> + .hsync_end = 752,
> + .htotal = 800,
> + .hskew = 0,
> + .vdisplay = 480,
> + .vsync_start = 490,
> + .vsync_end = 492,
> + .vtotal = 525,
> + .vscan = 0,
> + .vrefresh = 60,
> + .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> + .name = {"640x480-60"},
> + };
> + igt_output_override_mode(output, &override_mode);
> +
> + width = override_mode.hdisplay;
> + height = override_mode.vdisplay;
> +
> + ret = igt_create_fb(display->drm_fd, width, height, DRM_FORMAT_XRGB8888, tiling, &input_fb);
> + igt_assert(ret >= 0);
> +
> + ret = igt_create_fb(display->drm_fd, width, height, writeback_format, tiling, &output_fb);
> + igt_assert(ret >= 0);
> +
> + plane = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
> + igt_plane_set_fb(plane, &input_fb);
> + igt_output_set_writeback_fb(output, &output_fb);
> +
> + ret = igt_display_try_commit_atomic(display, DRM_MODE_ATOMIC_TEST_ONLY |
> + DRM_MODE_ATOMIC_ALLOW_MODESET, NULL);

Okay, we're using atomic test-only mode to know if we can perform tests
with the writeback output. It's probably fine, but we don't use
WRITEBACK_PIXEL_FORMATS, which makes me a little bit sad.

> + igt_plane_set_fb(plane, NULL);
> + igt_remove_fb(display->drm_fd, &input_fb);
> + igt_remove_fb(display->drm_fd, &output_fb);
> +
> + return !ret;
> +}
> +
> +static igt_output_t *kms_writeback_get_output(igt_display_t *display)
> +{
> + int i;
> +
> + for (i = 0; i < display->n_outputs; i++) {
> + igt_output_t *output = &display->outputs[i];
> + int j;
> +
> + if (output->config.connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
> + continue;
> +
> + kmstest_force_connector(display->drm_fd, output->config.connector, FORCE_CONNECTOR_ON);

Hmm. Is this really necessary? "Real" userspace won't do this, so I
don't think we need to either.

> + for (j = 0; j < igt_display_get_n_pipes(display); j++) {
> + igt_output_set_pipe(output, j);
> +
> + if (check_writeback_config(display, output)) {
> + igt_debug("Using connector %u:%s on pipe %d\n",
> + output->config.connector->connector_id,
> + output->name, j);
> + return output;
> + }

We could probably add an igt_debug statement in case we don't use this
writeback output.

> + }
> +
> + /* Restore any connectors we don't use, so we don't trip on them later */
> + kmstest_force_connector(display->drm_fd, output->config.connector, FORCE_CONNECTOR_UNSPECIFIED);
> + }
> +
> + return NULL;
> +}
> +
> +static void check_writeback_fb_id(igt_output_t *output)
> +{
> + uint64_t check_fb_id;
> +
> + check_fb_id = igt_output_get_prop(output, IGT_CONNECTOR_WRITEBACK_FB_ID);
> + igt_assert(check_fb_id == 0);
> +}
> +
> +static int do_writeback_test(igt_output_t *output, uint32_t flags,
> + uint32_t fb_id, int32_t *out_fence_ptr,
> + bool ptr_valid)

flags seems to always be set to DRM_MODE_ATOMIC_ALLOW_MODESET. We can
probably remove the parameter from this function.

> +{
> + int ret;
> + igt_display_t *display = output->display;
> + struct kmstest_connector_config *config = &output->config;
> +
> + igt_output_set_prop_value(output, IGT_CONNECTOR_CRTC_ID, config->crtc->crtc_id);
> + igt_output_set_prop_value(output, IGT_CONNECTOR_WRITEBACK_FB_ID, fb_id);
> + igt_output_set_prop_value(output, IGT_CONNECTOR_WRITEBACK_OUT_FENCE_PTR, (uint64_t)out_fence_ptr);
> +
> + if (ptr_valid)
> + *out_fence_ptr = 0;
> +
> + ret = igt_display_try_commit_atomic(display, flags, NULL);
> +
> + if (ptr_valid)
> + igt_assert(*out_fence_ptr == -1);

I'm confused. Why should this be -1 even if we
igt_display_try_commit_atomic succeeds?

> + /* WRITEBACK_FB_ID must always read as zero */
> + check_writeback_fb_id(output);
> +
> + return ret;
> +}
> +
> +static void invalid_out_fence(igt_output_t *output, igt_fb_t *valid_fb, igt_fb_t *invalid_fb)
> +{
> + int i, ret;
> + int32_t out_fence;
> + struct {
> + uint32_t fb_id;
> + bool ptr_valid;
> + int32_t *out_fence_ptr;
> + } invalid_tests[] = {
> + {
> + /* No output buffer, but the WRITEBACK_OUT_FENCE_PTR set. */
> + .fb_id = 0,
> + .ptr_valid = true,
> + .out_fence_ptr = &out_fence,
> + },
> + {
> + /* Invalid output buffer. */
> + .fb_id = invalid_fb->fb_id,
> + .ptr_valid = true,
> + .out_fence_ptr = &out_fence,
> + },

This doesn't belong in this function (invalid_out_fence), since this
checks an invalid framebuffer, not an invalid fence. We should probably
move it to writeback_fb_id (and rename that function to test_fb?).

> + {
> + /* Invalid WRITEBACK_OUT_FENCE_PTR. */
> + .fb_id = valid_fb->fb_id,
> + .ptr_valid = false,
> + .out_fence_ptr = (int32_t *)0x8,
> + },
> + };
> +
> + for (i = 0; i < ARRAY_SIZE(invalid_tests); i++) {
> + ret = do_writeback_test(output, DRM_MODE_ATOMIC_ALLOW_MODESET,
> + invalid_tests[i].fb_id,
> + invalid_tests[i].out_fence_ptr,
> + invalid_tests[i].ptr_valid);
> + igt_assert(ret != 0);

Maybe we can check for -ret == EINVAL?

> + }
> +}
> +
> +static void writeback_fb_id(igt_output_t *output, igt_fb_t *valid_fb, igt_fb_t *invalid_fb)

invalid_fb doesn't seem to be used here. valid_fb seems to be set to
the input framebuffer. It's probably not a good idea to use the same FB
for input and writeback output.

> +{
> +
> + int ret;
> +
> + /* Valid output buffer */
> + ret = do_writeback_test(output, DRM_MODE_ATOMIC_ALLOW_MODESET,
> + valid_fb->fb_id, NULL, false);
> + igt_assert(ret == 0);
> +
> + /* Invalid object for WRITEBACK_FB_ID */
> + ret = do_writeback_test(output, DRM_MODE_ATOMIC_ALLOW_MODESET,
> + output->id, NULL, false);
> + igt_assert(ret == -EINVAL);
> +
> + /* Zero WRITEBACK_FB_ID */
> + ret = do_writeback_test(output, DRM_MODE_ATOMIC_ALLOW_MODESET,
> + 0, NULL, false);
> + igt_assert(ret == 0);
> +}
> +
> +igt_main
> +{
> + igt_display_t display;
> + igt_output_t *output;
> + igt_plane_t *plane;
> + igt_fb_t input_fb;
> + drmModeModeInfo mode;
> + int ret;
> +
> + memset(&display, 0, sizeof(display));
> +
> + igt_fixture {
> + display.drm_fd = drm_open_driver_master(DRIVER_ANY);
> + igt_display_require(&display, display.drm_fd);
> +
> + kmstest_set_vt_graphics_mode();
> +
> + igt_display_require(&display, display.drm_fd);
> +
> + igt_require(display.is_atomic);
> +
> + output = kms_writeback_get_output(&display);
> + igt_require(output);
> +
> + if (output->use_override_mode)
> + memcpy(&mode, &output->override_mode, sizeof(mode));
> + else
> + memcpy(&mode, &output->config.default_mode, sizeof(mode));
> +
> + plane = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
> + igt_require(plane);

Maybe we can assert on this?

> + ret = igt_create_fb(display.drm_fd, mode.hdisplay,
> + mode.vdisplay,
> + DRM_FORMAT_XRGB8888,
> + igt_fb_mod_to_tiling(0),

This is supposed to take a modifier. DRM_FORMAT_MOD_LINEAR would be
better to make this clear.

(Applies to other lines of this patch)

> + &input_fb);
> + igt_assert(ret >= 0);
> + igt_plane_set_fb(plane, &input_fb);
> + }
> +
> + igt_subtest("writeback-pixel-formats") {
> + drmModePropertyBlobRes *formats_blob = get_writeback_formats_blob(output);

Need to drmModeFreePropertyBlob this.

> + const char *valid_chars = "0123456 ABCGNRUVXY";
> + unsigned int i;
> + char *c;
> +
> + /*
> + * We don't have a comprehensive list of formats, so just check
> + * that the blob length is sensible and that it doesn't contain
> + * any outlandish characters
> + */
> + igt_assert(!(formats_blob->length % 4));
> + c = formats_blob->data;
> + for (i = 0; i < formats_blob->length; i++)
> + igt_assert_f(strchr(valid_chars, c[i]),
> + "Unexpected character %c\n", c[i]);

Honestly, I'm not a fan of this check. There's no guarantee that fourcc
codes will be made from ASCII characters, in fact some formats already
have non-printable chars in them. I don't want to have to update this
test when a new fourcc format is added.

We currently don't have a test for IN_FORMATS. If we really want to
check formats, we could have a big array of known formats and add a
bool is_valid_format(uint32_t fmt) function.

> + }
> +
> + igt_subtest("writeback-invalid-out-fence") {
> + igt_fb_t invalid_fb;

invalid_output_fb would be a better name IMHO.

> + ret = igt_create_fb(display.drm_fd, mode.hdisplay / 2,
> + mode.vdisplay / 2,
> + DRM_FORMAT_XRGB8888,
> + igt_fb_mod_to_tiling(0),
> + &invalid_fb);
> + igt_require(ret > 0);

We should probably use a different variable: ret is signed,
igt_create_fb isn't. Also ret doesn't make it clear that the return
value is the KMS framebuffer ID.

(Applies to other subtests)

> + invalid_out_fence(output, &input_fb, &invalid_fb);

(Still not sure why we provide the input FB to this function.)

> + igt_remove_fb(display.drm_fd, &invalid_fb);
> + }
> +
> + igt_subtest("writeback-fb-id") {
> + igt_fb_t output_fb;
> + ret = igt_create_fb(display.drm_fd, mode.hdisplay, mode.vdisplay,
> + DRM_FORMAT_XRGB8888,
> + igt_fb_mod_to_tiling(0),
> + &output_fb);
> + igt_require(ret > 0);
> +
> + writeback_fb_id(output, &input_fb, &output_fb);
> +
> + igt_remove_fb(display.drm_fd, &output_fb);
> + }
> +
> + igt_fixture {
> + igt_remove_fb(display.drm_fd, &input_fb);
> + igt_display_fini(&display);
> + }
> +}
> diff --git a/tests/meson.build b/tests/meson.build
> index f168fbba..9c77cfcd 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -63,6 +63,7 @@ test_progs = [
> 'kms_universal_plane',
> 'kms_vblank',
> 'kms_vrr',
> + 'kms_writeback',
> 'meta_test',
> 'panfrost_get_param',
> 'panfrost_gem_new',
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