drm/core: Change declaration for gamma_set.

Change return value to int to propagate errors from gamma_set,
and remove start parameter. Updates always use the full size,
and some drivers even ignore the start parameter altogether.

This is needed for atomic drivers, where an atomic commit can
fail with -EINTR or -ENOMEM and should be restarted. This is already
and issue for drm_atomic_helper_legacy_set_gamma, which this patch
fixes up.

Changes since v1:
- Fix compiler warning. (Emil)
- Fix commit message (Daniel)

Cc: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Mathieu Larouche <mathieu.larouche@matrox.com>
Cc: Thierry Reding <treding@nvidia.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Improve commit message a bit more, mention that this fixes
the helper.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/742944bc-9f41-1acb-df4f-0fd4c8a10168@linux.intel.com

19 files changed, 85 insertions, 64 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
index 7e57447bf5f4..112e358f0f9b 100644
--- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
@@ -2667,19 +2667,21 @@ static void dce_v10_0_cursor_reset(struct drm_crtc *crtc)
 	}
 }
 
-static void dce_v10_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				    u16 *blue, uint32_t start, uint32_t size)
+static int dce_v10_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				    u16 *blue, uint32_t size)
 {
 	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
-	int end = (start + size > 256) ? 256 : start + size, i;
+	int i;
 
 	/* userspace palettes are always correct as is */
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		amdgpu_crtc->lut_r[i] = red[i] >> 6;
 		amdgpu_crtc->lut_g[i] = green[i] >> 6;
 		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
 	}
 	dce_v10_0_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 static void dce_v10_0_crtc_destroy(struct drm_crtc *crtc)
diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
index da101551960b..b522fa2435a8 100644
--- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
@@ -2678,19 +2678,21 @@ static void dce_v11_0_cursor_reset(struct drm_crtc *crtc)
 	}
 }
 
-static void dce_v11_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				    u16 *blue, uint32_t start, uint32_t size)
+static int dce_v11_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				    u16 *blue, uint32_t size)
 {
 	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
-	int end = (start + size > 256) ? 256 : start + size, i;
+	int i;
 
 	/* userspace palettes are always correct as is */
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		amdgpu_crtc->lut_r[i] = red[i] >> 6;
 		amdgpu_crtc->lut_g[i] = green[i] >> 6;
 		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
 	}
 	dce_v11_0_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 static void dce_v11_0_crtc_destroy(struct drm_crtc *crtc)
diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
index 41d9bc5f9c0e..b50ed72feedb 100644
--- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
@@ -2574,19 +2574,21 @@ static void dce_v8_0_cursor_reset(struct drm_crtc *crtc)
 	}
 }
 
-static void dce_v8_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				    u16 *blue, uint32_t start, uint32_t size)
+static int dce_v8_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				   u16 *blue, uint32_t size)
 {
 	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
-	int end = (start + size > 256) ? 256 : start + size, i;
+	int i;
 
 	/* userspace palettes are always correct as is */
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		amdgpu_crtc->lut_r[i] = red[i] >> 6;
 		amdgpu_crtc->lut_g[i] = green[i] >> 6;
 		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
 	}
 	dce_v8_0_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 static void dce_v8_0_crtc_destroy(struct drm_crtc *crtc)
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index c337922606e3..5957c3e659fe 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -624,19 +624,21 @@ static void ast_crtc_reset(struct drm_crtc *crtc)
 
 }
 
-static void ast_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				 u16 *blue, uint32_t start, uint32_t size)
+static int ast_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+			      u16 *blue, uint32_t size)
 {
 	struct ast_crtc *ast_crtc = to_ast_crtc(crtc);
-	int end = (start + size > 256) ? 256 : start + size, i;
+	int i;
 
 	/* userspace palettes are always correct as is */
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		ast_crtc->lut_r[i] = red[i] >> 8;
 		ast_crtc->lut_g[i] = green[i] >> 8;
 		ast_crtc->lut_b[i] = blue[i] >> 8;
 	}
 	ast_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 
diff --git a/drivers/gpu/drm/cirrus/cirrus_mode.c b/drivers/gpu/drm/cirrus/cirrus_mode.c
index 0b1a411cb89e..17c915d9a03e 100644
--- a/drivers/gpu/drm/cirrus/cirrus_mode.c
+++ b/drivers/gpu/drm/cirrus/cirrus_mode.c
@@ -325,18 +325,20 @@ static void cirrus_crtc_commit(struct drm_crtc *crtc)
  * use this for 8-bit mode so can't perform smooth fades on deeper modes,
  * but it's a requirement that we provide the function
  */
-static void cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				  u16 *blue, uint32_t start, uint32_t size)
+static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				 u16 *blue, uint32_t size)
 {
 	struct cirrus_crtc *cirrus_crtc = to_cirrus_crtc(crtc);
 	int i;
 
-	for (i = 0; i < CIRRUS_LUT_SIZE; i++) {
+	for (i = 0; i < size; i++) {
 		cirrus_crtc->lut_r[i] = red[i];
 		cirrus_crtc->lut_g[i] = green[i];
 		cirrus_crtc->lut_b[i] = blue[i];
 	}
 	cirrus_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 /* Simple cleanup function */
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 4342f3dfc0e1..191d84f12e67 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2920,16 +2920,15 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
  * @red: red correction table
  * @green: green correction table
  * @blue: green correction table
- * @start: first entry, must always be 0
  * @size: size of the tables
  *
  * Implements support for legacy gamma correction table for drivers
  * that support color management through the DEGAMMA_LUT/GAMMA_LUT
  * properties.
  */
-void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
-					u16 *red, u16 *green, u16 *blue,
-					uint32_t start, uint32_t size)
+int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
+				       u16 *red, u16 *green, u16 *blue,
+				       uint32_t size)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_mode_config *config = &dev->mode_config;
@@ -2941,7 +2940,7 @@ void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
 
 	state = drm_atomic_state_alloc(crtc->dev);
 	if (!state)
-		return;
+		return -ENOMEM;
 
 	blob = drm_property_create_blob(dev,
 					sizeof(struct drm_color_lut) * size,
@@ -2992,7 +2991,7 @@ retry:
 
 	drm_property_unreference_blob(blob);
 
-	return;
+	return 0;
 fail:
 	if (ret == -EDEADLK)
 		goto backoff;
@@ -3000,7 +2999,7 @@ fail:
 	drm_atomic_state_free(state);
 	drm_property_unreference_blob(blob);
 
-	return;
+	return ret;
 backoff:
 	drm_atomic_state_clear(state);
 	drm_atomic_legacy_backoff(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ba6174fc117c..889e01f1b3f2 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5172,7 +5172,7 @@ int drm_mode_gamma_set_ioctl(struct drm_device *dev,
 		goto out;
 	}
 
-	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
+	ret = crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, crtc->gamma_size);
 
 out:
 	drm_modeset_unlock_all(dev);
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 7590df5e2e72..58ed6e6d4f12 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -227,7 +227,7 @@ static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
 	g_base = r_base + crtc->gamma_size;
 	b_base = g_base + crtc->gamma_size;
 
-	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
+	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, crtc->gamma_size);
 }
 
 /**
diff --git a/drivers/gpu/drm/gma500/gma_display.c b/drivers/gpu/drm/gma500/gma_display.c
index c95406e6f44d..5b636bf0b467 100644
--- a/drivers/gpu/drm/gma500/gma_display.c
+++ b/drivers/gpu/drm/gma500/gma_display.c
@@ -175,20 +175,21 @@ void gma_crtc_load_lut(struct drm_crtc *crtc)
 	}
 }
 
-void gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green, u16 *blue,
-			u32 start, u32 size)
+int gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green, u16 *blue,
+		       u32 size)
 {
 	struct gma_crtc *gma_crtc = to_gma_crtc(crtc);
 	int i;
-	int end = (start + size > 256) ? 256 : start + size;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		gma_crtc->lut_r[i] = red[i] >> 8;
 		gma_crtc->lut_g[i] = green[i] >> 8;
 		gma_crtc->lut_b[i] = blue[i] >> 8;
 	}
 
 	gma_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 /**
diff --git a/drivers/gpu/drm/gma500/gma_display.h b/drivers/gpu/drm/gma500/gma_display.h
index b2491c65f053..e72dd08b701b 100644
--- a/drivers/gpu/drm/gma500/gma_display.h
+++ b/drivers/gpu/drm/gma500/gma_display.h
@@ -72,8 +72,8 @@ extern int gma_crtc_cursor_set(struct drm_crtc *crtc,
 			       uint32_t width, uint32_t height);
 extern int gma_crtc_cursor_move(struct drm_crtc *crtc, int x, int y);
 extern void gma_crtc_load_lut(struct drm_crtc *crtc);
-extern void gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-			       u16 *blue, u32 start, u32 size);
+extern int gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+			      u16 *blue, u32 size);
 extern void gma_crtc_dpms(struct drm_crtc *crtc, int mode);
 extern void gma_crtc_prepare(struct drm_crtc *crtc);
 extern void gma_crtc_commit(struct drm_crtc *crtc);
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 14e64e08909e..f6d5892d03f1 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -1344,19 +1344,20 @@ static void mga_crtc_commit(struct drm_crtc *crtc)
  * use this for 8-bit mode so can't perform smooth fades on deeper modes,
  * but it's a requirement that we provide the function
  */
-static void mga_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				  u16 *blue, uint32_t start, uint32_t size)
+static int mga_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+			      u16 *blue, uint32_t size)
 {
 	struct mga_crtc *mga_crtc = to_mga_crtc(crtc);
-	int end = (start + size > MGAG200_LUT_SIZE) ? MGAG200_LUT_SIZE : start + size;
 	int i;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		mga_crtc->lut_r[i] = red[i] >> 8;
 		mga_crtc->lut_g[i] = green[i] >> 8;
 		mga_crtc->lut_b[i] = blue[i] >> 8;
 	}
 	mga_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 /* Simple cleanup function */
diff --git a/drivers/gpu/drm/nouveau/dispnv04/crtc.c b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
index 6f318c54da33..0cb7a18cde26 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/crtc.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
@@ -785,14 +785,14 @@ nv_crtc_disable(struct drm_crtc *crtc)
 	nouveau_bo_ref(NULL, &disp->image[nv_crtc->index]);
 }
 
-static void
-nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
+static int
+nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
 		  uint32_t size)
 {
-	int end = (start + size > 256) ? 256 : start + size, i;
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
+	int i;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		nv_crtc->lut.r[i] = r[i];
 		nv_crtc->lut.g[i] = g[i];
 		nv_crtc->lut.b[i] = b[i];
@@ -805,10 +805,12 @@ nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
 	 */
 	if (!nv_crtc->base.primary->fb) {
 		nv_crtc->lut.depth = 0;
-		return;
+		return 0;
 	}
 
 	nv_crtc_gamma_load(crtc);
+
+	return 0;
 }
 
 static int
diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 3ffc2b0057bf..7a7788212df7 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1346,21 +1346,22 @@ nv50_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
 	return 0;
 }
 
-static void
+static int
 nv50_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
-		    uint32_t start, uint32_t size)
+		    uint32_t size)
 {
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
-	u32 end = min_t(u32, start + size, 256);
 	u32 i;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		nv_crtc->lut.r[i] = r[i];
 		nv_crtc->lut.g[i] = g[i];
 		nv_crtc->lut.b[i] = b[i];
 	}
 
 	nv50_crtc_lut_load(crtc);
+
+	return 0;
 }
 
 static void
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 2fb18f13395c..e85c7a2f565b 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -231,19 +231,21 @@ void radeon_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 	*blue = radeon_crtc->lut_b[regno] << 6;
 }
 
-static void radeon_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				  u16 *blue, uint32_t start, uint32_t size)
+static int radeon_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				 u16 *blue, uint32_t size)
 {
 	struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
-	int end = (start + size > 256) ? 256 : start + size, i;
+	int i;
 
 	/* userspace palettes are always correct as is */
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		radeon_crtc->lut_r[i] = red[i] >> 6;
 		radeon_crtc->lut_g[i] = green[i] >> 6;
 		radeon_crtc->lut_b[i] = blue[i] >> 6;
 	}
 	radeon_crtc_load_lut(crtc);
+
+	return 0;
 }
 
 static void radeon_crtc_destroy(struct drm_crtc *crtc)
@@ -688,6 +690,7 @@ radeon_crtc_set_config(struct drm_mode_set *set)
 	pm_runtime_put_autosuspend(dev->dev);
 	return ret;
 }
+
 static const struct drm_crtc_funcs radeon_crtc_funcs = {
 	.cursor_set2 = radeon_crtc_cursor_set2,
 	.cursor_move = radeon_crtc_cursor_move,
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index ba2e373ec901..4c0f26a644a3 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -175,20 +175,22 @@ vc4_crtc_lut_load(struct drm_crtc *crtc)
 		HVS_WRITE(SCALER_GAMDATA, vc4_crtc->lut_b[i]);
 }
 
-static void
+static int
 vc4_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
-		   uint32_t start, uint32_t size)
+		   uint32_t size)
 {
 	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 	u32 i;
 
-	for (i = start; i < start + size; i++) {
+	for (i = 0; i < size; i++) {
 		vc4_crtc->lut_r[i] = r[i] >> 8;
 		vc4_crtc->lut_g[i] = g[i] >> 8;
 		vc4_crtc->lut_b[i] = b[i] >> 8;
 	}
 
 	vc4_crtc_lut_load(crtc);
+
+	return 0;
 }
 
 static u32 vc4_get_fifo_full_level(u32 format)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 55231cce73a0..8a69d4da40b5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1404,9 +1404,9 @@ static int vmw_du_update_layout(struct vmw_private *dev_priv, unsigned num,
 	return 0;
 }
 
-void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
-			   u16 *r, u16 *g, u16 *b,
-			   uint32_t start, uint32_t size)
+int vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
+			  u16 *r, u16 *g, u16 *b,
+			  uint32_t size)
 {
 	struct vmw_private *dev_priv = vmw_priv(crtc->dev);
 	int i;
@@ -1418,6 +1418,8 @@ void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
 		vmw_write(dev_priv, SVGA_PALETTE_BASE + i * 3 + 1, g[i] >> 8);
 		vmw_write(dev_priv, SVGA_PALETTE_BASE + i * 3 + 2, b[i] >> 8);
 	}
+
+	return 0;
 }
 
 int vmw_du_connector_dpms(struct drm_connector *connector, int mode)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
index 57203212c501..ff4803c107bc 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
@@ -195,9 +195,9 @@ struct vmw_display_unit {
 void vmw_du_cleanup(struct vmw_display_unit *du);
 void vmw_du_crtc_save(struct drm_crtc *crtc);
 void vmw_du_crtc_restore(struct drm_crtc *crtc);
-void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
+int vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
 			   u16 *r, u16 *g, u16 *b,
-			   uint32_t start, uint32_t size);
+			   uint32_t size);
 int vmw_du_crtc_cursor_set2(struct drm_crtc *crtc, struct drm_file *file_priv,
 			    uint32_t handle, uint32_t width, uint32_t height,
 			    int32_t hot_x, int32_t hot_y);
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index b03bd83703b4..1877a7c18d8e 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -147,9 +147,9 @@ void
 __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state);
 void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
 					  struct drm_connector_state *state);
-void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
-					u16 *red, u16 *green, u16 *blue,
-					uint32_t start, uint32_t size);
+int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
+				       u16 *red, u16 *green, u16 *blue,
+				       uint32_t size);
 
 /**
  * drm_atomic_crtc_for_each_plane - iterate over planes currently attached to CRTC
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f59d8a2d8920..411be4f45506 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -479,8 +479,8 @@ struct drm_crtc_funcs {
 	 * going on, which should eventually be unified to just one set of
 	 * hooks.
 	 */
-	void (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
-			  uint32_t start, uint32_t size);
+	int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
+			 uint32_t size);
 
 	/**
 	 * @destroy: