Merge pull request #1157 from emersion/wlr-gamma-control

Implement wlr-gamma-control-unstable-v1

backend/drm/atomic.c

@@ -199,14 +199,18 @@ static bool atomic_crtc_move_cursor(struct wlr_drm_backend *drm,
 static bool atomic_crtc_set_gamma(struct wlr_drm_backend *drm,
 		struct wlr_drm_crtc *crtc, uint16_t *r, uint16_t *g, uint16_t *b,
 		uint32_t size) {
-	struct drm_color_lut gamma[size];
-
 	// Fallback to legacy gamma interface when gamma properties are not available
 	// (can happen on older intel gpu's that support gamma but not degamma)
 	if (crtc->props.gamma_lut == 0) {
 		return legacy_iface.crtc_set_gamma(drm, crtc, r, g, b, size);
 	}
 
+	struct drm_color_lut *gamma = malloc(size * sizeof(struct drm_color_lut));
+	if (gamma == NULL) {
+		wlr_log(WLR_ERROR, "Failed to allocate gamma table");
+		return false;
+	}
+
 	for (uint32_t i = 0; i < size; i++) {
 		gamma[i].red = r[i];
 		gamma[i].green = g[i];
@@ -218,10 +222,12 @@ static bool atomic_crtc_set_gamma(struct wlr_drm_backend *drm,
 	}
 
 	if (drmModeCreatePropertyBlob(drm->fd, gamma,
-				sizeof(struct drm_color_lut) * size, &crtc->gamma_lut)) {
+			size * sizeof(struct drm_color_lut), &crtc->gamma_lut)) {
+		free(gamma);
 		wlr_log_errno(WLR_ERROR, "Unable to create property blob");
 		return false;
 	}
+	free(gamma);
 
 	struct atomic atom;
 	atomic_begin(crtc, &atom);

backend/drm/drm.c

@@ -228,19 +228,12 @@ static bool drm_connector_swap_buffers(struct wlr_output *output,
 	return true;
 }
 
-static void drm_connector_set_gamma(struct wlr_output *output,
-		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b) {
-	struct wlr_drm_connector *conn = (struct wlr_drm_connector *)output;
-	struct wlr_drm_backend *drm = (struct wlr_drm_backend *)output->backend;
-	bool ok;
-
-	if (conn->crtc) {
-		ok = drm->iface->crtc_set_gamma(drm, conn->crtc, r, g, b, size);
-		if (ok) {
-			wlr_output_update_needs_swap(output);
-		}
+static void fill_empty_gamma_table(uint32_t size,
+		uint16_t *r, uint16_t *g, uint16_t *b) {
+	for (uint32_t i = 0; i < size; ++i) {
+		uint16_t val = (uint32_t)0xffff * i / (size - 1);
+		r[i] = g[i] = b[i] = val;
 	}
-
 }
 
 static uint32_t drm_connector_get_gamma_size(struct wlr_output *output) {
@@ -254,6 +247,37 @@ static uint32_t drm_connector_get_gamma_size(struct wlr_output *output) {
 	return 0;
 }
 
+static bool drm_connector_set_gamma(struct wlr_output *output,
+		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b) {
+	struct wlr_drm_connector *conn = (struct wlr_drm_connector *)output;
+	struct wlr_drm_backend *drm = (struct wlr_drm_backend *)output->backend;
+
+	if (!conn->crtc) {
+		return false;
+	}
+
+	uint16_t *reset_table = NULL;
+	if (size == 0) {
+		size = drm_connector_get_gamma_size(output);
+		reset_table = malloc(3 * size * sizeof(uint16_t));
+		if (reset_table == NULL) {
+			wlr_log(WLR_ERROR, "Failed to allocate gamma table");
+			return false;
+		}
+		r = reset_table;
+		g = reset_table + size;
+		b = reset_table + 2 * size;
+		fill_empty_gamma_table(size, r, g, b);
+	}
+
+	bool ok = drm->iface->crtc_set_gamma(drm, conn->crtc, r, g, b, size);
+	if (ok) {
+		wlr_output_update_needs_swap(output);
+	}
+	free(reset_table);
+	return ok;
+}
+
 static bool drm_connector_export_dmabuf(struct wlr_output *output,
 		struct wlr_dmabuf_attributes *attribs) {
 	struct wlr_drm_connector *conn = (struct wlr_drm_connector *)output;

examples/gamma-control.c

@@ -0,0 +1,195 @@
+#define _POSIX_C_SOURCE 200809L
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <wayland-client-protocol.h>
+#include <wayland-client.h>
+#include "wlr-gamma-control-unstable-v1-client-protocol.h"
+
+struct output {
+	struct wl_output *wl_output;
+	struct zwlr_gamma_control_v1 *gamma_control;
+	uint32_t ramp_size;
+	int table_fd;
+	uint16_t *table;
+	struct wl_list link;
+};
+
+static struct wl_list outputs;
+static struct zwlr_gamma_control_manager_v1 *gamma_control_manager = NULL;
+
+static int create_anonymous_file(off_t size) {
+	char template[] = "/tmp/wlroots-shared-XXXXXX";
+	int fd = mkstemp(template);
+	if (fd < 0) {
+		return -1;
+	}
+
+	int ret;
+	do {
+		errno = 0;
+		ret = ftruncate(fd, size);
+	} while (errno == EINTR);
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+
+	unlink(template);
+	return fd;
+}
+
+static int create_gamma_table(uint32_t ramp_size, uint16_t **table) {
+	size_t table_size = ramp_size * 3 * sizeof(uint16_t);
+	int fd = create_anonymous_file(table_size);
+	if (fd < 0) {
+		fprintf(stderr, "failed to create anonymous file\n");
+		return -1;
+	}
+
+	void *data =
+		mmap(NULL, table_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (data == MAP_FAILED) {
+		fprintf(stderr, "failed to mmap()\n");
+		close(fd);
+		return -1;
+	}
+
+	*table = data;
+	return fd;
+}
+
+static void gamma_control_handle_gamma_size(void *data,
+		struct zwlr_gamma_control_v1 *gamma_control, uint32_t ramp_size) {
+	struct output *output = data;
+	output->ramp_size = ramp_size;
+	output->table_fd = create_gamma_table(ramp_size, &output->table);
+	if (output->table_fd < 0) {
+		exit(EXIT_FAILURE);
+	}
+}
+
+static void gamma_control_handle_failed(void *data,
+		struct zwlr_gamma_control_v1 *gamma_control) {
+	fprintf(stderr, "failed to set gamma table\n");
+	exit(EXIT_FAILURE);
+}
+
+static const struct zwlr_gamma_control_v1_listener gamma_control_listener = {
+	.gamma_size = gamma_control_handle_gamma_size,
+	.failed = gamma_control_handle_failed,
+};
+
+static void registry_handle_global(void *data, struct wl_registry *registry,
+		uint32_t name, const char *interface, uint32_t version) {
+	if (strcmp(interface, wl_output_interface.name) == 0) {
+		struct output *output = calloc(1, sizeof(struct output));
+		output->wl_output = wl_registry_bind(registry, name,
+			&wl_output_interface, 1);
+		wl_list_insert(&outputs, &output->link);
+	} else if (strcmp(interface,
+			zwlr_gamma_control_manager_v1_interface.name) == 0) {
+		gamma_control_manager = wl_registry_bind(registry, name,
+			&zwlr_gamma_control_manager_v1_interface, 1);
+	}
+}
+
+static void registry_handle_global_remove(void *data,
+		struct wl_registry *registry, uint32_t name) {
+	// Who cares?
+}
+
+static const struct wl_registry_listener registry_listener = {
+	.global = registry_handle_global,
+	.global_remove = registry_handle_global_remove,
+};
+
+static void fill_gamma_table(uint16_t *table, uint32_t ramp_size,
+		double contrast, double brightness, double gamma) {
+	uint16_t *r = table;
+	uint16_t *g = table + ramp_size;
+	uint16_t *b = table + 2 * ramp_size;
+	for (uint32_t i = 0; i < ramp_size; ++i) {
+		double val = (double)i / (ramp_size - 1);
+		val = contrast * pow(val, 1.0 / gamma) + (brightness - 1);
+		if (val > 1.0) {
+			val = 1.0;
+		} else if (val < 0.0) {
+			val = 0.0;
+		}
+		r[i] = g[i] = b[i] = (uint16_t)(UINT16_MAX * val);
+	}
+}
+
+static const char usage[] = "usage: gamma-control [options]\n"
+	"  -h          show this help message\n"
+	"  -c <value>  set contrast (default: 1)\n"
+	"  -b <value>  set brightness (default: 1)\n"
+	"  -g <value>  set gamma (default: 1)\n";
+
+int main(int argc, char *argv[]) {
+	wl_list_init(&outputs);
+
+	double contrast = 1, brightness = 1, gamma = 1;
+	int opt;
+	while ((opt = getopt(argc, argv, "hc:b:g:")) != -1) {
+		switch (opt) {
+		case 'c':
+			contrast = strtod(optarg, NULL);
+			break;
+		case 'b':
+			brightness = strtod(optarg, NULL);
+			break;
+		case 'g':
+			gamma = strtod(optarg, NULL);
+			break;
+		case 'h':
+		default:
+			fprintf(stderr, usage);
+			return opt == 'h' ? EXIT_SUCCESS : EXIT_FAILURE;
+		}
+	}
+
+	struct wl_display *display = wl_display_connect(NULL);
+	if (display == NULL) {
+		fprintf(stderr, "failed to create display\n");
+		return -1;
+	}
+
+	struct wl_registry *registry = wl_display_get_registry(display);
+	wl_registry_add_listener(registry, &registry_listener, NULL);
+	wl_display_dispatch(display);
+	wl_display_roundtrip(display);
+
+	if (gamma_control_manager == NULL) {
+		fprintf(stderr,
+			"compositor doesn't support wlr-gamma-control-unstable-v1\n");
+		return EXIT_FAILURE;
+	}
+
+	struct output *output;
+	wl_list_for_each(output, &outputs, link) {
+		output->gamma_control = zwlr_gamma_control_manager_v1_get_gamma_control(
+			gamma_control_manager, output->wl_output);
+		zwlr_gamma_control_v1_add_listener(output->gamma_control,
+			&gamma_control_listener, output);
+	}
+	wl_display_roundtrip(display);
+
+	wl_list_for_each(output, &outputs, link) {
+		fill_gamma_table(output->table, output->ramp_size,
+			contrast, brightness, gamma);
+		zwlr_gamma_control_v1_set_gamma(output->gamma_control,
+			output->table_fd);
+	}
+
+	while (wl_display_dispatch(display) != -1) {
+		// This space is intentionnally left blank
+	}
+
+	return EXIT_SUCCESS;
+}

examples/meson.build

@@ -50,6 +50,12 @@ executable(
 	dependencies: [wayland_cursor, wayland_client, wlr_protos, wlroots]
 )
 
+executable(
+	'gamma-control',
+	'gamma-control.c',
+	dependencies: [wayland_cursor, wayland_client, wlr_protos, wlroots]
+)
+
 if libavutil.found() and libavcodec.found() and libavformat.found()
 	executable(
 		'dmabuf-capture',

include/rootston/desktop.h

@@ -4,6 +4,7 @@
 #include <wayland-server.h>
 #include <wlr/config.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_gamma_control_v1.h>
 #include <wlr/types/wlr_gamma_control.h>
 #include <wlr/types/wlr_idle_inhibit_v1.h>
 #include <wlr/types/wlr_idle.h>
@@ -43,6 +44,7 @@ struct roots_desktop {
 	struct wlr_xdg_shell_v6 *xdg_shell_v6;
 	struct wlr_xdg_shell *xdg_shell;
 	struct wlr_gamma_control_manager *gamma_control_manager;
+	struct wlr_gamma_control_manager_v1 *gamma_control_manager_v1;
 	struct wlr_screenshooter *screenshooter;
 	struct wlr_export_dmabuf_manager_v1 *export_dmabuf_manager_v1;
 	struct wlr_server_decoration_manager *server_decoration_manager;

include/wlr/interfaces/wlr_output.h

@@ -28,7 +28,7 @@ struct wlr_output_impl {
 	void (*destroy)(struct wlr_output *output);
 	bool (*make_current)(struct wlr_output *output, int *buffer_age);
 	bool (*swap_buffers)(struct wlr_output *output, pixman_region32_t *damage);
-	void (*set_gamma)(struct wlr_output *output,
+	bool (*set_gamma)(struct wlr_output *output,
 		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 	uint32_t (*get_gamma_size)(struct wlr_output *output);
 	bool (*export_dmabuf)(struct wlr_output *output,

include/wlr/types/wlr_gamma_control_v1.h

@@ -0,0 +1,31 @@
+#ifndef WLR_TYPES_WLR_GAMMA_CONTROL_V1_H
+#define WLR_TYPES_WLR_GAMMA_CONTROL_V1_H
+
+#include <wayland-server.h>
+
+struct wlr_gamma_control_manager_v1 {
+	struct wl_global *global;
+	struct wl_list resources;
+	struct wl_list controls; // wlr_gamma_control_v1::link
+
+	struct wl_listener display_destroy;
+
+	void *data;
+};
+
+struct wlr_gamma_control_v1 {
+	struct wl_resource *resource;
+	struct wlr_output *output;
+	struct wl_list link;
+
+	struct wl_listener output_destroy_listener;
+
+	void *data;
+};
+
+struct wlr_gamma_control_manager_v1 *wlr_gamma_control_manager_v1_create(
+	struct wl_display *display);
+void wlr_gamma_control_manager_v1_destroy(
+	struct wlr_gamma_control_manager_v1 *manager);
+
+#endif

include/wlr/types/wlr_output.h

@@ -174,9 +174,19 @@ bool wlr_output_swap_buffers(struct wlr_output *output, struct timespec *when,
  * it is a no-op.
  */
 void wlr_output_schedule_frame(struct wlr_output *output);
-void wlr_output_set_gamma(struct wlr_output *output,
-	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
+/**
+ * Returns the maximum length of each gamma ramp, or 0 if unsupported.
+ */
 uint32_t wlr_output_get_gamma_size(struct wlr_output *output);
+/**
+ * Sets the gamma table for this output. `r`, `g` and `b` are gamma ramps for
+ * red, green and blue. `size` is the length of the ramps and must not exceed
+ * the value returned by `wlr_output_get_gamma_size`.
+ *
+ * Providing zero-sized ramps resets the gamma table.
+ */
+bool wlr_output_set_gamma(struct wlr_output *output,
+	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 bool wlr_output_export_dmabuf(struct wlr_output *output,
 	struct wlr_dmabuf_attributes *attribs);
 void wlr_output_set_fullscreen_surface(struct wlr_output *output,

protocol/meson.build

@@ -42,6 +42,7 @@ protocols = [
 	'server-decoration.xml',
 	'virtual-keyboard-unstable-v1.xml',
 	'wlr-export-dmabuf-unstable-v1.xml',
+	'wlr-gamma-control-unstable-v1.xml',
 	'wlr-input-inhibitor-unstable-v1.xml',
 	'wlr-layer-shell-unstable-v1.xml',
 	'wlr-screencopy-unstable-v1.xml',
@@ -55,6 +56,7 @@ client_protocols = [
 	'idle.xml',
 	'screenshooter.xml',
 	'wlr-export-dmabuf-unstable-v1.xml',
+	'wlr-gamma-control-unstable-v1.xml',
 	'wlr-input-inhibitor-unstable-v1.xml',
 	'wlr-layer-shell-unstable-v1.xml',
 	'wlr-screencopy-unstable-v1.xml',

protocol/wlr-gamma-control-unstable-v1.xml

@@ -0,0 +1,126 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="wlr_gamma_control_unstable_v1">
+  <copyright>
+    Copyright © 2015 Giulio camuffo
+    Copyright © 2018 Simon Ser
+
+    Permission to use, copy, modify, distribute, and sell this
+    software and its documentation for any purpose is hereby granted
+    without fee, provided that the above copyright notice appear in
+    all copies and that both that copyright notice and this permission
+    notice appear in supporting documentation, and that the name of
+    the copyright holders not be used in advertising or publicity
+    pertaining to distribution of the software without specific,
+    written prior permission.  The copyright holders make no
+    representations about the suitability of this software for any
+    purpose.  It is provided "as is" without express or implied
+    warranty.
+
+    THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+    SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+    FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+    ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+    THIS SOFTWARE.
+  </copyright>
+
+  <description summary="manage gamma tables of outputs">
+    This protocol allows a privileged client to set the gamma tables for
+    outputs.
+
+    Warning! The protocol described in this file is experimental and
+    backward incompatible changes may be made. Backward compatible changes
+    may be added together with the corresponding interface version bump.
+    Backward incompatible changes are done by bumping the version number in
+    the protocol and interface names and resetting the interface version.
+    Once the protocol is to be declared stable, the 'z' prefix and the
+    version number in the protocol and interface names are removed and the
+    interface version number is reset.
+  </description>
+
+  <interface name="zwlr_gamma_control_manager_v1" version="1">
+    <description summary="manager to create per-output gamma controls">
+      This interface is a manager that allows creating per-output gamma
+      controls.
+    </description>
+
+    <request name="get_gamma_control">
+      <description summary="get a gamma control for an output">
+        Create a gamma control that can be used to adjust gamma tables for the
+        provided output.
+      </description>
+      <arg name="id" type="new_id" interface="zwlr_gamma_control_v1"/>
+      <arg name="output" type="object" interface="wl_output"/>
+    </request>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the manager">
+        All objects created by the manager will still remain valid, until their
+        appropriate destroy request has been called.
+      </description>
+    </request>
+  </interface>
+
+  <interface name="zwlr_gamma_control_v1" version="1">
+    <description summary="adjust gamma tables for an output">
+      This interface allows a client to adjust gamma tables for a particular
+      output.
+
+      The client will receive the gamma size, and will then be able to set gamma
+      tables. At any time the compositor can send a failed event indicating that
+      this object is no longer valid.
+
+      There must always be at most one gamma control object per output, which
+      has exclusive access to this particular output. When the gamma control
+      object is destroyed, the gamma table is restored to its original value.
+    </description>
+
+    <event name="gamma_size">
+      <description summary="size of gamma ramps">
+        Advertise the size of each gamma ramp.
+
+        This event is sent immediately when the gamma control object is created.
+      </description>
+      <arg name="size" type="uint" summary="number of elements in a ramp"/>
+    </event>
+
+    <enum name="error">
+      <entry name="invalid_gamma" value="1" summary="invalid gamma tables"/>
+    </enum>
+
+    <request name="set_gamma">
+      <description summary="set the gamma table">
+        Set the gamma table. The file descriptor can be memory-mapped to provide
+        the raw gamma table, which contains successive gamma ramps for the red,
+        green and blue channels. Each gamma ramp is an array of 16-byte unsigned
+        integers which has the same length as the gamma size.
+
+        The file descriptor data must have the same length as three times the
+        gamma size.
+      </description>
+      <arg name="fd" type="fd" summary="gamma table file descriptor"/>
+    </request>
+
+    <event name="failed">
+      <description summary="object no longer valid">
+        This event indicates that the gamma control is no longer valid. This
+        can happen for a number of reasons, including:
+        - The output doesn't support gamma tables
+        - Setting the gamma tables failed
+        - Another client already has exclusive gamma control for this output
+        - The compositor has transfered gamma control to another client
+
+        Upon receiving this event, the client should destroy this object.
+      </description>
+    </event>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy this control">
+        Destroys the gamma control object. If the object is still valid, this
+        restores the original gamma tables.
+      </description>
+    </request>
+  </interface>
+</protocol>

rootston/desktop.c

@@ -9,6 +9,7 @@
 #include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_export_dmabuf_v1.h>
 #include <wlr/types/wlr_gamma_control.h>
+#include <wlr/types/wlr_gamma_control_v1.h>
 #include <wlr/types/wlr_idle_inhibit_v1.h>
 #include <wlr/types/wlr_idle.h>
 #include <wlr/types/wlr_input_inhibitor.h>
@@ -868,6 +869,8 @@ struct roots_desktop *desktop_create(struct roots_server *server,
 
 	desktop->gamma_control_manager = wlr_gamma_control_manager_create(
 		server->wl_display);
+	desktop->gamma_control_manager_v1 = wlr_gamma_control_manager_v1_create(
+		server->wl_display);
 	desktop->screenshooter = wlr_screenshooter_create(server->wl_display);
 	desktop->export_dmabuf_manager_v1 =
 		wlr_export_dmabuf_manager_v1_create(server->wl_display);

types/meson.build

@@ -25,6 +25,7 @@ lib_wlr_types = static_library(
 		'wlr_cursor.c',
 		'wlr_export_dmabuf_v1.c',
 		'wlr_gamma_control.c',
+		'wlr_gamma_control_v1.c',
 		'wlr_idle_inhibit_v1.c',
 		'wlr_idle.c',
 		'wlr_input_device.c',

types/wlr_gamma_control.c

@@ -25,7 +25,7 @@ static void gamma_control_destroy(struct wlr_gamma_control *gamma_control) {
 
 static const struct gamma_control_interface gamma_control_impl;
 
-struct wlr_gamma_control *gamma_control_from_resource(
+static struct wlr_gamma_control *gamma_control_from_resource(
 		struct wl_resource *resource) {
 	assert(wl_resource_instance_of(resource, &gamma_control_interface,
 		&gamma_control_impl));
@@ -83,7 +83,7 @@ static const struct gamma_control_interface gamma_control_impl = {
 
 static const struct gamma_control_manager_interface gamma_control_manager_impl;
 
-struct wlr_gamma_control_manager *gamma_control_manager_from_resource(
+static struct wlr_gamma_control_manager *gamma_control_manager_from_resource(
 		struct wl_resource *resource) {
 	assert(wl_resource_instance_of(resource, &gamma_control_manager_interface,
 		&gamma_control_manager_impl));

types/wlr_gamma_control_v1.c

@@ -0,0 +1,264 @@
+#include <assert.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <wayland-server.h>
+#include <wlr/interfaces/wlr_output.h>
+#include <wlr/types/wlr_gamma_control_v1.h>
+#include <wlr/types/wlr_output.h>
+#include <wlr/util/log.h>
+#include "util/signal.h"
+#include "wlr-gamma-control-unstable-v1-protocol.h"
+
+#define GAMMA_CONTROL_MANAGER_V1_VERSION 1
+
+static void gamma_control_handle_destroy(struct wl_client *client,
+		struct wl_resource *resource) {
+	wl_resource_destroy(resource);
+}
+
+static void gamma_control_destroy(struct wlr_gamma_control_v1 *gamma_control) {
+	if (gamma_control == NULL) {
+		return;
+	}
+	wlr_output_set_gamma(gamma_control->output, 0, NULL, NULL, NULL);
+	wl_resource_set_user_data(gamma_control->resource, NULL);
+	wl_list_remove(&gamma_control->output_destroy_listener.link);
+	wl_list_remove(&gamma_control->link);
+	free(gamma_control);
+}
+
+static void gamma_control_send_failed(
+		struct wlr_gamma_control_v1 *gamma_control) {
+	zwlr_gamma_control_v1_send_failed(gamma_control->resource);
+	gamma_control_destroy(gamma_control);
+}
+
+static const struct zwlr_gamma_control_v1_interface gamma_control_impl;
+
+static struct wlr_gamma_control_v1 *gamma_control_from_resource(
+		struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource, &zwlr_gamma_control_v1_interface,
+		&gamma_control_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+static void gamma_control_handle_resource_destroy(struct wl_resource *resource) {
+	struct wlr_gamma_control_v1 *gamma_control =
+		gamma_control_from_resource(resource);
+	gamma_control_destroy(gamma_control);
+}
+
+static void gamma_control_handle_output_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_gamma_control_v1 *gamma_control =
+		wl_container_of(listener, gamma_control, output_destroy_listener);
+	gamma_control_destroy(gamma_control);
+}
+
+static void gamma_control_handle_set_gamma(struct wl_client *client,
+		struct wl_resource *gamma_control_resource, int fd) {
+	struct wlr_gamma_control_v1 *gamma_control =
+		gamma_control_from_resource(gamma_control_resource);
+	if (gamma_control == NULL) {
+		goto error_fd;
+	}
+
+	uint32_t ramp_size = wlr_output_get_gamma_size(gamma_control->output);
+	size_t table_size = ramp_size * 3 * sizeof(uint16_t);
+
+	// Refuse to block when reading
+	int fd_flags = fcntl(fd, F_GETFL, 0);
+	if (fd_flags == -1) {
+		wlr_log_errno(WLR_ERROR, "failed to get FD flags");
+		gamma_control_send_failed(gamma_control);
+		goto error_fd;
+	}
+	if (fcntl(fd, F_SETFL, fd_flags | O_NONBLOCK) == -1) {
+		wlr_log_errno(WLR_ERROR, "failed to set FD flags");
+		gamma_control_send_failed(gamma_control);
+		goto error_fd;
+	}
+
+	// Use the heap since gamma tables can be large
+	uint16_t *table = malloc(table_size);
+	if (table == NULL) {
+		wl_resource_post_no_memory(gamma_control_resource);
+		goto error_fd;
+	}
+
+	ssize_t n_read = read(fd, table, table_size);
+	if (n_read < 0) {
+		wlr_log_errno(WLR_ERROR, "failed to read gamma table");
+		gamma_control_send_failed(gamma_control);
+		goto error_table;
+	} else if ((size_t)n_read != table_size) {
+		wl_resource_post_error(gamma_control_resource,
+			ZWLR_GAMMA_CONTROL_V1_ERROR_INVALID_GAMMA,
+			"The gamma ramps don't have the correct size");
+		goto error_table;
+	}
+	close(fd);
+	fd = -1;
+
+	uint16_t *r = table;
+	uint16_t *g = table + ramp_size;
+	uint16_t *b = table + 2 * ramp_size;
+
+	bool ok = wlr_output_set_gamma(gamma_control->output, ramp_size, r, g, b);
+	if (!ok) {
+		gamma_control_send_failed(gamma_control);
+		goto error_table;
+	}
+	free(table);
+
+	return;
+
+error_table:
+	free(table);
+error_fd:
+	close(fd);
+}
+
+static const struct zwlr_gamma_control_v1_interface gamma_control_impl = {
+	.destroy = gamma_control_handle_destroy,
+	.set_gamma = gamma_control_handle_set_gamma,
+};
+
+static const struct zwlr_gamma_control_manager_v1_interface
+	gamma_control_manager_impl;
+
+static struct wlr_gamma_control_manager_v1 *gamma_control_manager_from_resource(
+		struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource,
+		&zwlr_gamma_control_manager_v1_interface, &gamma_control_manager_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+static void gamma_control_manager_get_gamma_control(struct wl_client *client,
+		struct wl_resource *manager_resource, uint32_t id,
+		struct wl_resource *output_resource) {
+	struct wlr_gamma_control_manager_v1 *manager =
+		gamma_control_manager_from_resource(manager_resource);
+	struct wlr_output *output = wlr_output_from_resource(output_resource);
+
+	struct wlr_gamma_control_v1 *gamma_control =
+		calloc(1, sizeof(struct wlr_gamma_control_v1));
+	if (gamma_control == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+	gamma_control->output = output;
+
+	uint32_t version = wl_resource_get_version(manager_resource);
+	gamma_control->resource = wl_resource_create(client,
+		&zwlr_gamma_control_v1_interface, version, id);
+	if (gamma_control->resource == NULL) {
+		free(gamma_control);
+		wl_client_post_no_memory(client);
+		return;
+	}
+	wl_resource_set_implementation(gamma_control->resource, &gamma_control_impl,
+		gamma_control, gamma_control_handle_resource_destroy);
+
+	wl_signal_add(&output->events.destroy,
+		&gamma_control->output_destroy_listener);
+	gamma_control->output_destroy_listener.notify =
+		gamma_control_handle_output_destroy;
+
+	wl_list_init(&gamma_control->link);
+
+	if (!output->impl->set_gamma) {
+		zwlr_gamma_control_v1_send_failed(gamma_control->resource);
+		gamma_control_destroy(gamma_control);
+		return;
+	}
+
+	struct wlr_gamma_control_v1 *gc;
+	wl_list_for_each(gc, &manager->controls, link) {
+		if (gc->output == output) {
+			zwlr_gamma_control_v1_send_failed(gc->resource);
+			gamma_control_destroy(gc);
+			return;
+		}
+	}
+
+	wl_list_remove(&gamma_control->link);
+	wl_list_insert(&manager->controls, &gamma_control->link);
+	zwlr_gamma_control_v1_send_gamma_size(gamma_control->resource,
+		wlr_output_get_gamma_size(output));
+}
+
+static const struct zwlr_gamma_control_manager_v1_interface
+		gamma_control_manager_impl = {
+	.get_gamma_control = gamma_control_manager_get_gamma_control,
+};
+
+static void gamma_control_manager_handle_resource_destroy(
+		struct wl_resource *resource) {
+	wl_list_remove(wl_resource_get_link(resource));
+}
+
+static void gamma_control_manager_bind(struct wl_client *client, void *data,
+		uint32_t version, uint32_t id) {
+	struct wlr_gamma_control_manager_v1 *manager = data;
+
+	struct wl_resource *resource = wl_resource_create(client,
+		&zwlr_gamma_control_manager_v1_interface, version, id);
+	if (resource == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+	wl_resource_set_implementation(resource, &gamma_control_manager_impl,
+		manager, gamma_control_manager_handle_resource_destroy);
+	wl_list_insert(&manager->resources, wl_resource_get_link(resource));
+}
+
+void wlr_gamma_control_manager_v1_destroy(
+		struct wlr_gamma_control_manager_v1 *manager) {
+	if (!manager) {
+		return;
+	}
+	wl_list_remove(&manager->display_destroy.link);
+	struct wlr_gamma_control_v1 *gamma_control, *tmp;
+	wl_list_for_each_safe(gamma_control, tmp, &manager->controls, link) {
+		wl_resource_destroy(gamma_control->resource);
+	}
+	struct wl_resource *resource, *resource_tmp;
+	wl_resource_for_each_safe(resource, resource_tmp, &manager->resources) {
+		wl_resource_destroy(resource);
+	}
+	wl_global_destroy(manager->global);
+	free(manager);
+}
+
+static void handle_display_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_gamma_control_manager_v1 *manager =
+		wl_container_of(listener, manager, display_destroy);
+	wlr_gamma_control_manager_v1_destroy(manager);
+}
+
+struct wlr_gamma_control_manager_v1 *wlr_gamma_control_manager_v1_create(
+		struct wl_display *display) {
+	struct wlr_gamma_control_manager_v1 *manager =
+		calloc(1, sizeof(struct wlr_gamma_control_manager_v1));
+	if (!manager) {
+		return NULL;
+	}
+
+	manager->global = wl_global_create(display,
+		&zwlr_gamma_control_manager_v1_interface,
+		GAMMA_CONTROL_MANAGER_V1_VERSION, manager, gamma_control_manager_bind);
+	if (manager->global == NULL) {
+		free(manager);
+		return NULL;
+	}
+
+	wl_list_init(&manager->resources);
+	wl_list_init(&manager->controls);
+
+	manager->display_destroy.notify = handle_display_destroy;
+	wl_display_add_destroy_listener(display, &manager->display_destroy);
+
+	return manager;
+}

types/wlr_output.c

@@ -552,11 +552,12 @@ void wlr_output_schedule_frame(struct wlr_output *output) {
 		wl_event_loop_add_idle(ev, schedule_frame_handle_idle_timer, output);
 }
 
-void wlr_output_set_gamma(struct wlr_output *output,
-	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b) {
-	if (output->impl->set_gamma) {
-		output->impl->set_gamma(output, size, r, g, b);
+bool wlr_output_set_gamma(struct wlr_output *output, uint32_t size,
+		uint16_t *r, uint16_t *g, uint16_t *b) {
+	if (!output->impl->set_gamma) {
+		return false;
 	}
+	return output->impl->set_gamma(output, size, r, g, b);
 }
 
 uint32_t wlr_output_get_gamma_size(struct wlr_output *output) {