From: Thomas Zimmermann Date: Mon, 2 Jan 2023 11:29:16 +0000 (+0100) Subject: drm/format-helper: Comment on RGB888 byte order X-Git-Tag: v6.3-rc1~135^2~25^2~84 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a5b1a681dcac2eb75129e5e1bc2530dbd6febc44;p=thirdparty%2Flinux.git 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: Thomas Zimmermann Reviewed-by: Maíra Canal Reviewed-by: José Expósito Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-3-tzimmermann@suse.de --- diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 74ff33c2ddaa5..b98bd7c5caeeb 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -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; diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c index 2191e57f22972..cd1d7da3483c1 100644 --- a/drivers/gpu/drm/tests/drm_format_helper_test.c +++ b/drivers/gpu/drm/tests/drm_format_helper_test.c @@ -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, ¶ms->clip); KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0); }