Re: [igt-dev] [PATCH i-g-t] tests/kms_concurrent: Test maximum number of planes supported by the platform

Kahola, Mika
2020-03-26T08:20:13Z

-----Original Message-----
From: Lisovskiy, Stanislav <stanislav.lisovskiy@intel.com>
Sent: Thursday, March 26, 2020 10:04 AM
To: Kahola, Mika <mika.kahola@intel.com>
Cc: igt-dev@lists.freedesktop.org; juhapekka.heikkla@gmail.com
Subject: Re: [igt-dev] [PATCH i-g-t] tests/kms_concurrent: Test maximum number of planes supported by the platform

On Thu, Mar 26, 2020 at 09:09:28AM +0200, Mika Kahola wrote:
> There was an error in commit 0ab05a51a059 on computing number of
> maximum supported planes. This patch proposes a fix to this commit by
> first computing the number of planes that are within platform's
> bandwidth requirements, resets the display and then executes the actual testing.
>
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
> tests/kms_concurrent.c | 104
> +++++++++++++++++++----------------------
> 1 file changed, 47 insertions(+), 57 deletions(-)
>
> diff --git a/tests/kms_concurrent.c b/tests/kms_concurrent.c index
> 61137139..98a115da 100644
> --- a/tests/kms_concurrent.c
> +++ b/tests/kms_concurrent.c
> @@ -195,6 +195,27 @@ prepare_planes(data_t *data, enum pipe pipe, int max_planes,
> igt_plane_set_fb(data->plane[primary->index],
> &data->fb[primary->index]); }
>
> +static int test_bandwidth(data_t *data, enum pipe pipe, igt_output_t
> +*output) {
> +
> + int n_planes = data->display.pipes[pipe].n_planes;
> + int max_planes;
> + int i;
> + int ret;
> +
> + igt_pipe_refresh(&data->display, pipe, true);
> +
> + for (i = 1; i <= n_planes; i++) {
> + prepare_planes(data, pipe, i, output);
> + ret = igt_display_try_commit2(&data->display, COMMIT_ATOMIC | DRM_MODE_ATOMIC_TEST_ONLY);
> + if (ret != 0)
> + break; => this will leave max_planes ununitialized if commit fails for i==1
> + max_planes = i;
> + }
> +
> + return max_planes;
> +}

This code might return uninitialized max_planes. For example you start cycle, igt_display_commit2 returns non-zero, then you break, but max_planes is left uninitialized and then garbage is returned.

You actually don't even need max_planes variable - could just return i - 1, thus avoiding unnecessary assignments or otherwise should initialize max_planes with 0.

Stan

You're propably right. One shouldn't take granted that variable is initialized as 0. Actually, that wouldn't make any sense either. I'll go by returning i-1 as you proposed.

Thanks for the review!

Cheers,
Mika
> +
> static void
> test_plane_position_with_output(data_t *data, enum pipe pipe, int max_planes,
> igt_output_t *output)
> @@ -208,7 +229,7 @@ test_plane_position_with_output(data_t *data, enum pipe pipe, int max_planes,
> i = 0;
> while (i < iterations || loop_forever) {
> prepare_planes(data, pipe, max_planes, output);
> - igt_display_try_commit2(&data->display, COMMIT_ATOMIC);
> + igt_display_commit2(&data->display, COMMIT_ATOMIC);
> i++;
> }
> }
> @@ -241,44 +262,17 @@ get_lowres_mode(data_t *data, const drmModeModeInfo *mode_default,
> return mode;
> }
>
> -static int
> +static void
> test_resolution_with_output(data_t *data, enum pipe pipe,
> igt_output_t *output) {
> const drmModeModeInfo *mode_hi, *mode_lo;
> int iterations = opt.iterations < 1 ? 1 : opt.iterations;
> bool loop_forever = opt.iterations == LOOP_FOREVER ? true : false;
> - int i, c, ret;
> - int max_planes = data->display.pipes[pipe].n_planes;
> - igt_plane_t *primary;
> - drmModeModeInfo *mode;
> + int i;
>
> i = 0;
> while (i < iterations || loop_forever) {
> igt_output_set_pipe(output, pipe);
> - for (c = 0; c < max_planes; c++) {
> - igt_plane_t *plane = igt_output_get_plane(output, c);
> -
> - if (plane->type != DRM_PLANE_TYPE_PRIMARY)
> - continue;
> - primary = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
> - data->plane[primary->index] = primary;
> - mode = igt_output_get_mode(output);
> - igt_create_color_fb(data->drm_fd, mode->hdisplay, mode->vdisplay,
> - DRM_FORMAT_XRGB8888,
> - LOCAL_I915_FORMAT_MOD_X_TILED,
> - 0.0f, 0.0f, 1.0f,
> - &data->fb[primary->index]);
> - igt_plane_set_fb(data->plane[primary->index], &data->fb[primary->index]);
> - ret = igt_display_try_commit2(&data->display, COMMIT_ATOMIC);
> - if (ret) {
> - igt_plane_set_fb(data->plane[i], NULL);
> - igt_remove_fb(data->drm_fd, &data->fb[i]);
> - data->plane[i] = NULL;
> - break;
> - }
> - }
> - max_planes = c;
> - igt_assert_lt(0, max_planes);
>
> mode_hi = igt_output_get_mode(output);
> mode_lo = get_lowres_mode(data, mode_hi, output); @@ -293,48
> +287,35 @@ test_resolution_with_output(data_t *data, enum pipe pipe,
> igt_output_t *output)
>
> i++;
> }
> -
> - return max_planes;
> }
>
> static void
> -run_test(data_t *data, enum pipe pipe, igt_output_t *output)
> +run_test(data_t *data, enum pipe pipe, int max_planes, igt_output_t
> +*output)
> {
> - int connected_outs;
> - int n_planes = data->display.pipes[pipe].n_planes;
> - int max_planes = n_planes;
> -
> if (!opt.user_seed)
> opt.seed = time(NULL);
>
> - connected_outs = 0;
> - for_each_valid_output_on_pipe(&data->display, pipe, output) {
> - igt_info("Testing resolution with connector %s using pipe %s with seed %d\n",
> - igt_output_name(output), kmstest_pipe_name(pipe), opt.seed);
> -
> - test_init(data, pipe, n_planes, output);
> - max_planes = test_resolution_with_output(data, pipe, output);
> -
> - igt_fork(child, 1) {
> - test_plane_position_with_output(data, pipe, max_planes, output);
> - }
> + igt_info("Testing resolution with connector %s using pipe %s with seed %d\n",
> + igt_output_name(output), kmstest_pipe_name(pipe), opt.seed);
>
> - test_resolution_with_output(data, pipe, output);
> + test_init(data, pipe, max_planes, output);
> + igt_fork(child, 1) {
> + test_plane_position_with_output(data, pipe, max_planes, output);
> + }
>
> - igt_waitchildren();
> + test_resolution_with_output(data, pipe, output);
>
> - test_fini(data, pipe, n_planes, output);
> + igt_waitchildren();
>
> - connected_outs++;
> - }
> + test_fini(data, pipe, max_planes, output);
>
> - igt_skip_on(connected_outs == 0);
> }
>
> static void
> run_tests_for_pipe(data_t *data, enum pipe pipe) {
> igt_output_t *output;
> + int max_planes;
>
> igt_fixture {
> int valid_tests = 0;
> @@ -348,9 +329,18 @@ run_tests_for_pipe(data_t *data, enum pipe pipe)
> igt_require_f(valid_tests, "no valid crtc/connector combinations found\n");
> }
>
> - igt_subtest_f("pipe-%s", kmstest_pipe_name(pipe))
> - for_each_valid_output_on_pipe(&data->display, pipe, output)
> - run_test(data, pipe, output);
> + igt_subtest_f("pipe-%s", kmstest_pipe_name(pipe)) {
> + for_each_valid_output_on_pipe(&data->display, pipe, output) {
> + int n_planes = data->display.pipes[pipe].n_planes;
> +
> + test_init(data, pipe, n_planes, output);
> + max_planes = test_bandwidth(data, pipe, output);
> + test_fini(data, pipe, n_planes, output);
> +
> + igt_display_reset(&data->display);
> + run_test(data, pipe, max_planes, output);
> + }
> + }
> }
>
> static int opt_handler(int option, int option_index, void *input)
> --
> 2.20.1
>
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