Re: [igt-dev] [PATCH V6 i-g-t 4/6] kms_writeback: Add writeback-check-output

Ser, Simon
2019-07-12T12:34:26Z

Mostly looks good, here are a few comments.

On Wed, 2019-06-12 at 23:17 -0300, Brian Starkey wrote:
> Add a test which makes commits using the writeback connector, and
> checks the output buffer hash to make sure it is/isn't written as
> appropriate.
>
> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
> ---
> tests/kms_writeback.c | 124 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 124 insertions(+)
>
> diff --git a/tests/kms_writeback.c b/tests/kms_writeback.c
> index 66ef48a6..0f20dadd 100644
> --- a/tests/kms_writeback.c
> +++ b/tests/kms_writeback.c
> @@ -30,6 +30,7 @@
> #include "igt.h"
> #include "igt_core.h"
> #include "igt_fb.h"
> +#include "sw_sync.h"
>
> static drmModePropertyBlobRes *get_writeback_formats_blob(igt_output_t *output)
> {
> @@ -221,6 +222,116 @@ static void writeback_fb_id(igt_output_t *output, igt_fb_t *valid_fb, igt_fb_t *
> igt_assert(ret == 0);
> }
>
> +static void fill_fb(igt_fb_t *fb, double color[3])
> +{
> + cairo_t *cr = igt_get_cairo_ctx(fb->fd, fb);
> + igt_assert(cr);
> +
> + igt_paint_color(cr, 0, 0, fb->width, fb->height,
> + color[0], color[1], color[2]);
> +}
> +
> +static void get_and_wait_out_fence(igt_output_t *output)
> +{
> + int ret;
> +
> + igt_assert(output->writeback_out_fence_fd >= 0);
> +
> + ret = sync_fence_wait(output->writeback_out_fence_fd, 1000);
> + igt_assert(ret == 0);

When filtering failures in CI Bug Log, "ret == 0" is not very helpful
and may not be unique. Can we add a descriptive error message, with
something among the lines of:

igt_assert_f(ret == 0, "sync_fence_wait failed: %s\n", strerror(-ret));

> + close(output->writeback_out_fence_fd);
> + output->writeback_out_fence_fd = -1;
> +}
> +
> +static void writeback_sequence(igt_output_t *output, igt_plane_t *plane,
> + igt_fb_t *in_fb, igt_fb_t *out_fbs[], int n_commits)
> +{
> + int i, color_idx = 0;
> + double in_fb_colors[2][3] = {
> + { 1.0, 0.0, 0.0 },
> + { 0.0, 1.0, 0.0 },
> + };
> + double clear_color[3] = { 1.0, 1.0, 1.0 };
> + igt_crc_t cleared_crc, out_expected;
> +
> + for (i = 0; i < n_commits; i++, color_idx++) {
> + /* Change the input color each time */
> + fill_fb(in_fb, in_fb_colors[color_idx % 2]);

Why do we need two indexes (i and color_idx)? I think [i % 2] should
work just fine.

> + if (out_fbs[i]) {
> + igt_crc_t out_before;
> +
> + /* Get the expected CRC */
> + fill_fb(out_fbs[i], in_fb_colors[color_idx % 2]);
> + igt_fb_get_crc(out_fbs[i], &out_expected);

Using out_fbs[i] to compute the expected CRC is a little bit confusing.
I think we can just use in_fb here (which is already filled with the
proper color).

> + fill_fb(out_fbs[i], clear_color);
> + if (i == 0)
> + igt_fb_get_crc(out_fbs[i], &cleared_crc);
> + igt_fb_get_crc(out_fbs[i], &out_before);
> + igt_assert_crc_equal(&cleared_crc, &out_before);
> + }
> +
> + /* Commit */
> + igt_plane_set_fb(plane, in_fb);
> + igt_output_set_writeback_fb(output, out_fbs[i]);
> +
> + igt_display_commit_atomic(output->display,
> + DRM_MODE_ATOMIC_ALLOW_MODESET,
> + NULL);
> + if (out_fbs[i])
> + get_and_wait_out_fence(output);
> +
> + /* Make sure the old output buffer is untouched */
> + if (i > 0 && out_fbs[i - 1] && (out_fbs[i] != out_fbs[i - 1])) {

Nit: unnecessary parentheses here

> + igt_crc_t out_prev;
> + igt_fb_get_crc(out_fbs[i - 1], &out_prev);
> + igt_assert_crc_equal(&cleared_crc, &out_prev);
> + }
> +
> + /* Make sure this output buffer is written */
> + if (out_fbs[i]) {
> + igt_crc_t out_after;
> + igt_fb_get_crc(out_fbs[i], &out_after);
> + igt_assert_crc_equal(&out_expected, &out_after);
> +
> + /* And clear it, for the next time */
> + fill_fb(out_fbs[i], clear_color);
> + }
> + }
> +}
> +
> +static void writeback_check_output(igt_output_t *output, igt_plane_t *plane,
> + igt_fb_t *input_fb, igt_fb_t *output_fb)
> +{
> + igt_fb_t *out_fbs[2] = { 0 };
> + igt_fb_t second_out_fb;
> + int ret;
> +
> + /* One commit, with a writeback. */
> + writeback_sequence(output, plane, input_fb, &output_fb, 1);
> +
> + /* Two commits, the second with no writeback */
> + out_fbs[0] = output_fb;
> + writeback_sequence(output, plane, input_fb, out_fbs, 2);
> +
> + /* Two commits, both with writeback */
> + out_fbs[1] = output_fb;
> + writeback_sequence(output, plane, input_fb, out_fbs, 2);
> +
> + ret = igt_create_fb(output_fb->fd, output_fb->width, output_fb->height,
> + DRM_FORMAT_XRGB8888,
> + igt_fb_mod_to_tiling(0),
> + &second_out_fb);
> + igt_require(ret > 0);

unsigned int cast to int here

> + /* Two commits, with different writeback buffers */
> + out_fbs[1] = &second_out_fb;
> + writeback_sequence(output, plane, input_fb, out_fbs, 2);
> +
> + igt_remove_fb(output_fb->fd, &second_out_fb);
> +}
> +
> igt_main
> {
> igt_display_t display;
> @@ -307,6 +418,19 @@ igt_main
> igt_remove_fb(display.drm_fd, &output_fb);
> }
>
> + igt_subtest("writeback-check-output") {
> + 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);

unsigned int cast to int here

> + writeback_check_output(output, plane, &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);
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