[PATCH 02/11] drm/vkms: allow color curve LUTs to have different sizes

Leandro Ribeiro <[email protected]> Tue, 4 Aug 2026 17:33:42 -0300
Newsgroups gmane.linux.kernel,gmane.comp.video.dri.devel
Message-ID <[email protected]>
Instead of keeping a hardcoded size that all LUTs representing color
curves must use, use ARRAY_SIZE() instead.

Besides making the code clearer, this allows us to create optimal LUTs
for each color curve, and each of them can naturally have a different
size. In the next commits we introduce these optimal LUTs.

Signed-off-by: Leandro Ribeiro <[email protected]>
---
 drivers/gpu/drm/vkms/tests/vkms_color_test.c |  4 ++--
 drivers/gpu/drm/vkms/vkms_luts.c             | 12 ++++++------
 drivers/gpu/drm/vkms/vkms_luts.h             |  2 --
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_test.c b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
index 1a1c7cac2f15..18e73a8a5c31 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_color_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
@@ -128,7 +128,7 @@ static void vkms_color_test_lerp(struct kunit *test)
 
 static void vkms_color_test_linear(struct kunit *test)
 {
-	for (int i = 0; i < LUT_SIZE; i++) {
+	for (int i = 0; i < linear_eotf.lut_length; i++) {
 		int linear = apply_lut_to_channel_value(&linear_eotf, i * 0x101, LUT_RED);
 
 		KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(linear, 0x101), i);
@@ -139,7 +139,7 @@ static void vkms_color_srgb_inv_srgb(struct kunit *test)
 {
 	u16 srgb, final;
 
-	for (int i = 0; i < LUT_SIZE; i++) {
+	for (int i = 0; i < srgb_eotf.lut_length; i++) {
 		srgb = apply_lut_to_channel_value(&srgb_eotf, i * 0x101, LUT_RED);
 		final = apply_lut_to_channel_value(&srgb_inv_eotf, srgb, LUT_RED);
 
diff --git a/drivers/gpu/drm/vkms/vkms_luts.c b/drivers/gpu/drm/vkms/vkms_luts.c
index 82cb792f10d8..6dcdef26bda8 100644
--- a/drivers/gpu/drm/vkms/vkms_luts.c
+++ b/drivers/gpu/drm/vkms/vkms_luts.c
@@ -12,7 +12,7 @@
  * https://gitlab.freedesktop.org/hwentland/lutgen
  */
 
-static struct drm_color_lut linear_array[LUT_SIZE] = {
+static struct drm_color_lut linear_array[] = {
 	{ 0x0, 0x0, 0x0, 0 },
 	{ 0x101, 0x101, 0x101, 0 },
 	{ 0x202, 0x202, 0x202, 0 },
@@ -273,12 +273,12 @@ static struct drm_color_lut linear_array[LUT_SIZE] = {
 
 const struct vkms_color_lut linear_eotf = {
 	.base = linear_array,
-	.lut_length = LUT_SIZE,
+	.lut_length = ARRAY_SIZE(linear_array),
 	.channel_value2index_ratio = 0xff00ffll
 };
 EXPORT_SYMBOL(linear_eotf);
 
-static struct drm_color_lut srgb_array[LUT_SIZE] = {
+static struct drm_color_lut srgb_array[] = {
 	{ 0x0, 0x0, 0x0, 0 },
 	{ 0x13, 0x13, 0x13, 0 },
 	{ 0x27, 0x27, 0x27, 0 },
@@ -539,12 +539,12 @@ static struct drm_color_lut srgb_array[LUT_SIZE] = {
 
 const struct vkms_color_lut srgb_eotf = {
 	.base = srgb_array,
-	.lut_length = LUT_SIZE,
+	.lut_length = ARRAY_SIZE(srgb_array),
 	.channel_value2index_ratio = 0xff00ffll
 };
 EXPORT_SYMBOL(srgb_eotf);
 
-static struct drm_color_lut srgb_inv_array[LUT_SIZE] = {
+static struct drm_color_lut srgb_inv_array[] = {
 	{ 0x0, 0x0, 0x0, 0 },
 	{ 0xcc2, 0xcc2, 0xcc2, 0 },
 	{ 0x15be, 0x15be, 0x15be, 0 },
@@ -805,7 +805,7 @@ static struct drm_color_lut srgb_inv_array[LUT_SIZE] = {
 
 const struct vkms_color_lut srgb_inv_eotf = {
 	.base = srgb_inv_array,
-	.lut_length = LUT_SIZE,
+	.lut_length = ARRAY_SIZE(srgb_inv_array),
 	.channel_value2index_ratio = 0xff00ffll
 };
 EXPORT_SYMBOL(srgb_inv_eotf);
diff --git a/drivers/gpu/drm/vkms/vkms_luts.h b/drivers/gpu/drm/vkms/vkms_luts.h
index 925a4a7b84e2..8078ab33b83e 100644
--- a/drivers/gpu/drm/vkms/vkms_luts.h
+++ b/drivers/gpu/drm/vkms/vkms_luts.h
@@ -3,8 +3,6 @@
 #ifndef _VKMS_LUTS_H_
 #define _VKMS_LUTS_H_
 
-#define LUT_SIZE 256
-
 extern const struct vkms_color_lut linear_eotf;
 extern const struct vkms_color_lut srgb_eotf;
 extern const struct vkms_color_lut srgb_inv_eotf;
-- 
2.55.0