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16 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
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22 * Author: Tiago Vignatti
25 * \file setbacklight.c
26 * Test program to get a backlight connector and set its brightness value.
27 * Queries for the connectors id can be performed using drm/tests/modeprint
36 #include <xf86drmMode.h>
38 #include "libbacklight.h"
41 get_drm_connector_type(struct udev_device *drm_device, uint32_t connector_id)
44 int fd, i, connector_type;
46 drmModeConnectorPtr connector;
48 filename = udev_device_get_devnode(drm_device);
49 fd = open(filename, O_RDWR | O_CLOEXEC);
51 printf("couldn't open drm_device\n");
55 res = drmModeGetResources(fd);
57 printf("Failed to get resources from card\n");
62 for (i = 0; i < res->count_connectors; i++) {
63 connector = drmModeGetConnector(fd, res->connectors[i]);
67 if ((connector->connection == DRM_MODE_DISCONNECTED) ||
68 (connector->connector_id != connector_id)) {
69 drmModeFreeConnector(connector);
73 connector_type = connector->connector_type;
74 drmModeFreeConnector(connector);
75 drmModeFreeResources(res);
78 return connector_type;
82 drmModeFreeResources(res);
86 /* returns a value between 0-255 range, where higher is brighter */
88 get_normalized_backlight(struct backlight *backlight)
90 long brightness, max_brightness;
93 brightness = backlight_get_brightness(backlight);
94 max_brightness = backlight_get_max_brightness(backlight);
96 /* convert it to a scale of 0 to 255 */
97 norm = (brightness * 255)/(max_brightness);
103 set_backlight(struct udev_device *drm_device, int connector_id, int blight)
106 long max_brightness, brightness, actual_brightness;
107 struct backlight *backlight;
110 connector_type = get_drm_connector_type(drm_device, connector_id);
111 if (connector_type < 0)
114 backlight = backlight_init(drm_device, connector_type);
116 printf("backlight adjust failed\n");
120 max_brightness = backlight_get_max_brightness(backlight);
121 printf("Max backlight: %ld\n", max_brightness);
123 brightness = backlight_get_brightness(backlight);
124 printf("Cached backlight: %ld\n", brightness);
126 actual_brightness = backlight_get_actual_brightness(backlight);
127 printf("Hardware backlight: %ld\n", actual_brightness);
129 printf("normalized current brightness: %d\n",
130 get_normalized_backlight(backlight));
132 /* denormalized value */
133 new_blight = (blight * max_brightness) / 255;
135 backlight_set_brightness(backlight, new_blight);
136 printf("Setting brightness to: %ld (norm: %d)\n", new_blight, blight);
138 backlight_destroy(backlight);
142 main(int argc, char **argv)
144 int blight, connector_id;
147 struct udev_enumerate *e;
148 struct udev_list_entry *entry;
149 struct udev_device *drm_device;
152 printf("Please add connector_id and brightness values from 0-255\n");
156 connector_id = atoi(argv[1]);
157 blight = atoi(argv[2]);
161 printf("failed to initialize udev context\n");
165 e = udev_enumerate_new(udev);
166 udev_enumerate_add_match_subsystem(e, "drm");
167 udev_enumerate_add_match_sysname(e, "card[0-9]*");
169 udev_enumerate_scan_devices(e);
171 udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
172 path = udev_list_entry_get_name(entry);
173 drm_device = udev_device_new_from_syspath(udev, path);
177 if (drm_device == NULL) {
178 printf("no drm device found\n");
182 set_backlight(drm_device, connector_id, blight);
184 udev_device_unref(drm_device);