Commit a5b1a681 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/format-helper: Comment on RGB888 byte order 



RGB888 is different than the other formats as most of its pixels are
unaligned and therefore helper functions do not use endianness conversion
helpers. Comment on this in the source code.

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarMaíra Canal <mcanal@igalia.com>
Reviewed-by: default avatarJosé Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-3-tzimmermann@suse.de
parent f35cd3fa

drivers/gpu/drm/drm_format_helper.c

+1 −0
Original line number Diff line number Diff line
@@ -404,6 +404,7 @@ static void drm_fb_xrgb8888_to_rgb888_line(void *dbuf, const void *sbuf, unsigne 


	for (x = 0; x < pixels; x++) {

		pix = le32_to_cpu(sbuf32[x]);

		/* write blue-green-red to output in little endianness */

		*dbuf8++ = (pix & 0x000000FF) >>  0;

		*dbuf8++ = (pix & 0x0000FF00) >>  8;

		*dbuf8++ = (pix & 0x00FF0000) >> 16;

drivers/gpu/drm/tests/drm_format_helper_test.c

+4 −0
Original line number Diff line number Diff line
@@ -407,6 +407,10 @@ static void drm_test_fb_xrgb8888_to_rgb888(struct kunit *test) 
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xrgb8888);

	iosys_map_set_vaddr(&src, xrgb8888);



	/*

	 * RGB888 expected results are already in little-endian

	 * order, so there's no need to convert the test output.

	 */

	drm_fb_xrgb8888_to_rgb888(&dst, &result->dst_pitch, &src, &fb, &params->clip);

	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);

}