Re: [PATCH 04/11] drm/vkms: remove linear_eotf

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `vkms_color_test_linear` KUnit test loop relies on a hardcoded multiplier of `0x101` that was designed for a 256-element LUT. The patch replaces `linear_eotf` (256 elements) with `test_linear_lut` (16 elements) without adjusting the multiplier. Since the loop now only executes 16 times (`i` from 0 to 15), the evaluated channel values only range from `0x0000` to `0x0F0F` (~5.8% of the 16-bit color space). The test fails to exercise the remaining 94% of the color range and leaves 14 out of the 16 elements of `test_linear_lut` completely untested. To restore proper test coverage over the `0x0000` to `0xFFFF` range, both instances of `0x101` should be updated to `0x1111` (since `15 * 0x1111 = 0xFFFF`).
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--- Patch [4]: [PATCH 04/11] drm/vkms: remove linear_eotf ---
commit e4769cf1ca6d6dd3c89f50766f7a24a69c53cccb
Author: Leandro Ribeiro <leandro.ribeiro@collabora.com>

drm/vkms: remove linear_eotf

This patch removes the linear_eotf LUT, which was only used for testing,
and updates the kunit color tests to use test_linear_lut instead.

> diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_test.c b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
> index 3489513af3527..28614edb8eb18 100644
> --- a/drivers/gpu/drm/vkms/tests/vkms_color_test.c
> +++ b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
> @@ -126,8 +126,8 @@ static void vkms_color_test_lerp(struct kunit *test)
>  
>  static void vkms_color_test_linear(struct kunit *test)
>  {
> -	for (int i = 0; i < linear_eotf.lut_length; i++) {
> -		int linear = apply_lut_to_channel_value(&linear_eotf, i * 0x101, LUT_RED);
> +	for (int i = 0; i < test_linear_lut.lut_length; i++) {
> +		int linear = apply_lut_to_channel_value(&test_linear_lut, i * 0x101, LUT_RED);

[Severity: Medium]
Since the new test_linear_lut only has 16 elements (compared to the 256
elements in linear_eotf), does leaving the multiplier as 0x101 mean we
only test values up to 0x0f0f (~5.8% of the 16-bit color space)?

Should both instances of 0x101 in this loop be updated to 0x1111 so that
the final iteration (15 * 0x1111) reaches 0xffff, restoring coverage over
the full color range?

>  
> -		KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(linear, 0x101), i);
> +		KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(linear, 0x101), i);
>  	}

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260804203351.148521-1-leandro.ribeiro@collabora.com?part=4