diff --git a/include/libweston/libweston.h b/include/libweston/libweston.h
index eef3cbe46..a2f9b0a7a 100644
--- a/include/libweston/libweston.h
+++ b/include/libweston/libweston.h
@@ -437,13 +437,6 @@ struct weston_output {
 	void (*set_backlight)(struct weston_output *output, uint32_t value);
 	void (*set_dpms)(struct weston_output *output, enum dpms_enum level);
 
-	uint16_t gamma_size;
-	void (*set_gamma)(struct weston_output *output,
-			  uint16_t size,
-			  uint16_t *r,
-			  uint16_t *g,
-			  uint16_t *b);
-
 	bool enabled; /**< is in the output_list, not pending list */
 
 	struct weston_color_profile *color_profile;
diff --git a/libweston/backend-drm/drm-internal.h b/libweston/backend-drm/drm-internal.h
index 0b3e44ce8..23fe9ab32 100644
--- a/libweston/backend-drm/drm-internal.h
+++ b/libweston/backend-drm/drm-internal.h
@@ -586,8 +586,8 @@ struct drm_output {
 	unsigned max_bpc;
 	enum wdrm_colorspace connector_colorspace;
 
-	bool deprecated_gamma_is_set;
 	bool legacy_gamma_not_supported;
+	uint16_t legacy_gamma_size;
 
 	/* Plane being displayed directly on the CRTC */
 	struct drm_plane *scanout_plane;
@@ -794,10 +794,6 @@ drm_pending_state_apply(struct drm_pending_state *pending_state);
 int
 drm_pending_state_apply_sync(struct drm_pending_state *pending_state);
 
-void
-drm_output_set_gamma(struct weston_output *output_base,
-		     uint16_t size, uint16_t *r, uint16_t *g, uint16_t *b);
-
 void
 drm_output_update_msc(struct drm_output *output, unsigned int seq);
 void
diff --git a/libweston/backend-drm/drm-virtual.c b/libweston/backend-drm/drm-virtual.c
index 4ad56aba7..3e540d1c5 100644
--- a/libweston/backend-drm/drm-virtual.c
+++ b/libweston/backend-drm/drm-virtual.c
@@ -318,8 +318,6 @@ drm_virtual_output_enable(struct weston_output *output_base)
 	output->base.assign_planes = drm_assign_planes;
 	output->base.set_dpms = NULL;
 	output->base.switch_mode = NULL;
-	output->base.gamma_size = 0;
-	output->base.set_gamma = NULL;
 
 	weston_compositor_stack_plane(b->compositor,
 				      &output->scanout_plane->base,
diff --git a/libweston/backend-drm/drm.c b/libweston/backend-drm/drm.c
index 14fc0c163..aa3f2bdd6 100644
--- a/libweston/backend-drm/drm.c
+++ b/libweston/backend-drm/drm.c
@@ -2045,7 +2045,7 @@ drm_output_set_content_type(struct weston_output *base,
 }
 
 static int
-drm_output_init_gamma_size(struct drm_output *output)
+drm_output_init_legacy_gamma_size(struct drm_output *output)
 {
 	struct drm_device *device = output->device;
 	drmModeCrtc *crtc;
@@ -2056,7 +2056,7 @@ drm_output_init_gamma_size(struct drm_output *output)
 	if (!crtc)
 		return -1;
 
-	output->base.gamma_size = crtc->gamma_size;
+	output->legacy_gamma_size = crtc->gamma_size;
 
 	drmModeFreeCrtc(crtc);
 
@@ -2507,7 +2507,7 @@ drm_output_enable(struct weston_output *base)
 	if (ret < 0)
 		goto err_crtc;
 
-	if (drm_output_init_gamma_size(output) < 0)
+	if (drm_output_init_legacy_gamma_size(output) < 0)
 		goto err_planes;
 
 	if (b->pageflip_timeout)
@@ -2536,7 +2536,6 @@ drm_output_enable(struct weston_output *base)
 	output->base.assign_planes = drm_assign_planes;
 	output->base.set_dpms = drm_set_dpms;
 	output->base.switch_mode = drm_output_switch_mode;
-	output->base.set_gamma = drm_output_set_gamma;
 
 	if (device->atomic_modeset)
 		weston_output_update_capture_info(base, WESTON_OUTPUT_CAPTURE_SOURCE_WRITEBACK,
diff --git a/libweston/backend-drm/kms.c b/libweston/backend-drm/kms.c
index 1affc104e..a80bea944 100644
--- a/libweston/backend-drm/kms.c
+++ b/libweston/backend-drm/kms.c
@@ -703,28 +703,6 @@ drm_plane_supports_color_range(struct drm_plane *plane,
 	return enum_info->valid;
 }
 
-void
-drm_output_set_gamma(struct weston_output *output_base,
-		     uint16_t size, uint16_t *r, uint16_t *g, uint16_t *b)
-{
-	int rc;
-	struct drm_output *output = to_drm_output(output_base);
-	struct drm_device *device = output->device;
-
-	assert(output);
-
-	/* check */
-	if (output_base->gamma_size != size)
-		return;
-
-	output->deprecated_gamma_is_set = true;
-	rc = drmModeCrtcSetGamma(device->drm.fd,
-				 output->crtc->crtc_id,
-				 size, r, g, b);
-	if (rc)
-		weston_log("set gamma failed: %s\n", strerror(errno));
-}
-
 /**
  * Mark an output state as current on the output, i.e. it has been
  * submitted to the kernel. The mode argument determines whether this
@@ -842,7 +820,7 @@ err:
 static void
 drm_output_reset_legacy_gamma(struct drm_output *output)
 {
-	uint32_t len = output->base.gamma_size;
+	uint32_t len = output->legacy_gamma_size;
 	uint16_t *lut;
 	uint32_t i;
 	int ret;
@@ -955,8 +933,7 @@ drm_output_apply_state_legacy(struct drm_output_state *state)
 			goto err;
 		}
 
-		if (!output->deprecated_gamma_is_set)
-			drm_output_reset_legacy_gamma(output);
+		drm_output_reset_legacy_gamma(output);
 	}
 
 	pinfo = scanout_state->fb->format;
@@ -1344,12 +1321,9 @@ drm_output_apply_state_atomic(struct drm_output_state *state,
 				     current_mode->blob_id);
 		ret |= crtc_add_prop(req, crtc, WDRM_CRTC_ACTIVE, 1);
 
-		if (!output->deprecated_gamma_is_set) {
-			ret |= crtc_add_prop_zero_ok(req, crtc,
-						     WDRM_CRTC_GAMMA_LUT, 0);
-			ret |= crtc_add_prop_zero_ok(req, crtc,
-						     WDRM_CRTC_DEGAMMA_LUT, 0);
-		}
+		ret |= crtc_add_prop_zero_ok(req, crtc, WDRM_CRTC_GAMMA_LUT, 0);
+		ret |= crtc_add_prop_zero_ok(req, crtc, WDRM_CRTC_DEGAMMA_LUT, 0);
+
 		ret |= crtc_add_prop_zero_ok(req, crtc, WDRM_CRTC_CTM, 0);
 		ret |= crtc_add_prop_zero_ok(req, crtc, WDRM_CRTC_VRR_ENABLED,
 					     wdrm_vrr_enabled_from_output(output));