Re: [igt-dev] [PATCH i-g-t v2] tests/kms_cursor_crc: refactoring cursor-alpha subtests

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Oct 21, 2020 at 05:59:56AM -0300, Melissa Wen wrote:
> Considering just a fully opaque or fully transparent cursor is not enough
> to check the composition of an ARGB cursor plane. For example, the cairo
> ARGB32 format uses pre-multiplied alpha, and this representation may only
> be evident when testing a translucent cursor.
> 
> Therefore, this patch refactors the cursor-alpha-opaque and
> cursor-alpha-transparent subtests into just one subtest (cursor-alpha)
> that checks the alpha blending of a white cursor, with different alpha
> values, in the primary plane. This refactoring also generates some setup
> stuffs savings.

Black background means you can't actually tell the
difference between premultiplied blending and no
blending.

Oh, I guess restore_image() does end up painting
the test pattern into the primary plane's fb? Are
we guaranteed to position the cursor over some non-black
parts?

The other obvious concern is whether hardware and software
blending will produce the exact same results or not. I do see
you use 1/4 steps for the alpha, which I guess can make that
more likely.

Side note: data->primary_fb[RESTOREBUFFER] looks to be dead weight

> 
> v2:
> - debug log states the alpha whenever CRC mismatch (Arek)
> - checking all alpha values before asserting the result (Arek)
> 
> Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
> ---
>  tests/kms_cursor_crc.c | 87 ++++++++++++++++++++++--------------------
>  1 file changed, 45 insertions(+), 42 deletions(-)
> 
> diff --git a/tests/kms_cursor_crc.c b/tests/kms_cursor_crc.c
> index 0be8f7f8..83c74a69 100644
> --- a/tests/kms_cursor_crc.c
> +++ b/tests/kms_cursor_crc.c
> @@ -428,65 +428,73 @@ static void prepare_crtc(data_t *data, igt_output_t *output,
>  	igt_pipe_crc_start(data->pipe_crc);
>  }
>  
> -static void test_cursor_alpha(data_t *data, double a)
> +static void test_cursor_alpha(data_t *data)
>  {
>  	igt_display_t *display = &data->display;
>  	igt_pipe_crc_t *pipe_crc = data->pipe_crc;
> -	igt_crc_t crc, ref_crc;
> +	igt_crc_t crc[5], ref_crc;
>  	cairo_t *cr;
>  	uint32_t fb_id;
>  	int curw = data->curw;
>  	int curh = data->curh;
> +	int i, index;
> +	double alpha;
> +	bool mismatch = false;
>  
> -	/* Alpha cursor fb with white color */
> +	/* Alpha cursor fb */
>  	fb_id = igt_create_fb(data->drm_fd, curw, curh,
>  				    DRM_FORMAT_ARGB8888,
>  				    LOCAL_DRM_FORMAT_MOD_NONE,
>  				    &data->fb);
>  	igt_assert(fb_id);
> +
> +	/*
> +	 * Hardware Test
> +	 * With the cursor enabled, get the PF CRCs from the composition with a
> +	 * white cursor with different alpha values.
> +	 */
>  	cr = igt_get_cairo_ctx(data->drm_fd, &data->fb);
> -	igt_paint_color_alpha(cr, 0, 0, curw, curh, 1.0, 1.0, 1.0, a);
> -	igt_put_cairo_ctx(cr);
> +	cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
>  
> -	/* Hardware Test - enable cursor and get PF CRC */
>  	cursor_enable(data);
> -	igt_display_commit(display);
> -	igt_wait_for_vblank(data->drm_fd,
> -			display->pipes[data->pipe].crtc_offset);
> -	igt_pipe_crc_get_current(data->drm_fd, pipe_crc, &crc);
> +	for (i = 0, alpha = 1.0; alpha >= 0.0; alpha -= 0.25, i++) {
> +		igt_paint_color_alpha(cr, 0, 0, curw, curh, 1.0, 1.0, 1.0, alpha);
> +
> +		igt_display_commit(display);
> +		igt_wait_for_vblank(data->drm_fd,
> +				    display->pipes[data->pipe].crtc_offset);
> +		igt_pipe_crc_get_current(data->drm_fd, pipe_crc, &crc[i]);
> +	}
> +	igt_put_cairo_ctx(cr);
>  
>  	cursor_disable(data);
>  	igt_remove_fb(data->drm_fd, &data->fb);
>  
> -	/* Software Test - render cursor in software, drawn it directly on PF */
> +	/* Software Test - render cursor in software, drawn it directly on PF*/
>  	cr = igt_get_cairo_ctx(data->drm_fd, &data->primary_fb[FRONTBUFFER]);
> -	igt_paint_color_alpha(cr, 0, 0, curw, curh, 1.0, 1.0, 1.0, a);
> -	igt_put_cairo_ctx(cr);
> -
> -	igt_display_commit(display);
> -	igt_wait_for_vblank(data->drm_fd,
> -			display->pipes[data->pipe].crtc_offset);
> -	igt_pipe_crc_get_current(data->drm_fd, pipe_crc, &ref_crc);
>  
> -	/* Compare CRC from Hardware/Software tests */
> -	igt_assert_crc_equal(&crc, &ref_crc);
> +	for (i = 0, alpha = 1.0; alpha >= 0.0; alpha -= 0.25, i++) {
> +		igt_paint_color_alpha(cr, 0, 0, curw, curh, 1.0, 1.0, 1.0, alpha);
>  
> -	/*Clear Screen*/
> -	cr = igt_get_cairo_ctx(data->drm_fd, &data->primary_fb[FRONTBUFFER]);
> -	igt_paint_color(cr, 0, 0, data->screenw, data->screenh,
> -			0.0, 0.0, 0.0);
> -	igt_put_cairo_ctx(cr);
> -}
> +		igt_display_commit(display);
> +		igt_wait_for_vblank(data->drm_fd,
> +				display->pipes[data->pipe].crtc_offset);
> +		igt_pipe_crc_get_current(data->drm_fd, pipe_crc, &ref_crc);
>  
> -static void test_cursor_transparent(data_t *data)
> -{
> -	test_cursor_alpha(data, 0.0);
> +		/* Compare CRC from Hardware/Software tests */
> +		if (igt_find_crc_mismatch(&crc[i], &ref_crc, &index)) {
> +			mismatch = true;
> +			igt_debug("CRC mismatch for alpha %.2f: 0x%x != 0x%x\n",
> +				  alpha, crc[i].crc[index], ref_crc.crc[index]);
> +		}
>  
> -}
> +		/*Clear Screen*/
> +		igt_paint_color(cr, 0, 0, data->screenw, data->screenh,
> +				0.0, 0.0, 0.0);
> +	}
> +	igt_put_cairo_ctx(cr);
>  
> -static void test_cursor_opaque(data_t *data)
> -{
> -	test_cursor_alpha(data, 1.0);
> +	igt_assert_f(!mismatch, "At least one CRC mismatch detected\n");
>  }
>  
>  static void run_test(data_t *data, void (*testfunc)(data_t *), int cursor_w, int cursor_h)
> @@ -655,15 +663,10 @@ static void run_tests_on_pipe(data_t *data, enum pipe pipe)
>  		run_test(data, test_cursor_size,
>  			 data->cursor_max_w, data->cursor_max_h);
>  
> -	igt_describe("Validates the composition of a fully opaque cursor "
> -		     "plane, i.e., alpha channel equal to 1.0.");
> -	igt_subtest_f("pipe-%s-cursor-alpha-opaque", kmstest_pipe_name(pipe))
> -		run_test(data, test_cursor_opaque, data->cursor_max_w, data->cursor_max_h);
> -
> -	igt_describe("Validates the composition of a fully transparent cursor "
> -		     "plane, i.e., alpha channel equal to 0.0.");
> -	igt_subtest_f("pipe-%s-cursor-alpha-transparent", kmstest_pipe_name(pipe))
> -		run_test(data, test_cursor_transparent, data->cursor_max_w, data->cursor_max_h);
> +	igt_describe("Validates the composition of alpha cursor plane "
> +		     "from fully opaque to fully transparent alpha range");
> +	igt_subtest_f("pipe-%s-cursor-alpha", kmstest_pipe_name(pipe))
> +		run_test(data, test_cursor_alpha, data->cursor_max_w, data->cursor_max_h);
>  
>  	igt_fixture
>  		create_cursor_fb(data, data->cursor_max_w, data->cursor_max_h);
> -- 
> 2.28.0
> 
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-- 
Ville Syrjälä
Intel
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