device: Always use a pair of driver and subdev names to find the device (MR 9)

Otherwise Megapixels fails to find the correct device on systems where
there are multiple media devices handled by the same driver, like imx8mq.

src/device.c

@@ -74,11 +74,12 @@ xioctl(int fd, int request, void *arg)
 }
 
 MPDevice *
-mp_device_find(const char *driver_name)
+mp_device_find(const char *driver_name, const char *dev_name)
 {
         MPDeviceList *list = mp_device_list_new();
 
-        MPDevice *found_device = mp_device_list_find_remove(&list, driver_name);
+        MPDevice *found_device =
+                mp_device_list_find_remove(&list, driver_name, dev_name);
 
         mp_device_list_free(list);
 
@@ -476,7 +477,9 @@ mp_device_list_free(MPDeviceList *device_list)
 }
 
 MPDevice *
-mp_device_list_find_remove(MPDeviceList **list, const char *driver_name)
+mp_device_list_find_remove(MPDeviceList **list,
+                           const char *driver_name,
+                           const char *dev_name)
 {
         MPDevice *found_device = NULL;
         int length = strlen(driver_name);
@@ -485,7 +488,8 @@ mp_device_list_find_remove(MPDeviceList **list, const char *driver_name)
                 MPDevice *device = mp_device_list_get(*list);
                 const struct media_device_info *info = mp_device_get_info(device);
 
-                if (strncmp(info->driver, driver_name, length) == 0) {
+                if (strncmp(info->driver, driver_name, length) == 0 &&
+                    mp_device_find_entity(device, dev_name)) {
                         found_device = mp_device_list_remove(list);
                         break;
                 }

src/device.h

@@ -12,7 +12,7 @@ mp_find_device_path(struct media_v2_intf_devnode devnode, char *path, int length
 
 typedef struct _MPDevice MPDevice;
 
-MPDevice *mp_device_find(const char *driver_name);
+MPDevice *mp_device_find(const char *driver_name, const char *dev_name);
 MPDevice *mp_device_open(const char *path);
 MPDevice *mp_device_new(int fd);
 void mp_device_close(MPDevice *device);
@@ -74,7 +74,8 @@ MPDeviceList *mp_device_list_new();
 void mp_device_list_free(MPDeviceList *device_list);
 
 MPDevice *mp_device_list_find_remove(MPDeviceList **device_list,
-                                     const char *driver_name);
+                                     const char *driver_name,
+                                     const char *dev_name);
 MPDevice *mp_device_list_remove(MPDeviceList **device_list);
 
 MPDevice *mp_device_list_get(const MPDeviceList *device_list);

src/io_pipeline.c

@@ -54,6 +54,7 @@ struct camera_info {
 
 struct device_info {
         const char *media_dev_name; // owned by camera config
+        const char *dev_name; // owned by camera config
 
         MPDevice *device;
 
@@ -132,8 +133,10 @@ setup_camera(MPDeviceList **device_list, const struct mp_camera_config *config)
         // Find device info
         size_t device_index = 0;
         for (; device_index < num_devices; ++device_index) {
-                if (strcmp(config->media_dev_name,
-                           devices[device_index].media_dev_name) == 0) {
+                if ((strcmp(config->media_dev_name,
+                            devices[device_index].media_dev_name) == 0) &&
+                    (strcmp(config->dev_name, devices[device_index].dev_name) ==
+                     0)) {
                         break;
                 }
         }
@@ -144,8 +147,9 @@ setup_camera(MPDeviceList **device_list, const struct mp_camera_config *config)
                 // Initialize new device
                 struct device_info *info = &devices[device_index];
                 info->media_dev_name = config->media_dev_name;
-                info->device = mp_device_list_find_remove(device_list,
-                                                          info->media_dev_name);
+                info->dev_name = config->dev_name;
+                info->device = mp_device_list_find_remove(
+                        device_list, info->media_dev_name, info->dev_name);
                 if (!info->device) {
                         g_printerr("Could not find /dev/media* node matching '%s'\n",
                                    info->media_dev_name);

tools/camera_test.c

@@ -19,22 +19,18 @@ get_time()
 int
 main(int argc, char *argv[])
 {
-        if (argc != 2 && argc != 3) {
-                printf("Usage: %s <media_device_name> [<sub_device_name>]\n",
-                       argv[0]);
+        if (argc != 3) {
+                printf("Usage: %s <media_device_name> <sub_device_name>\n", argv[0]);
                 return 1;
         }
 
         char *video_name = argv[1];
-        char *subdev_name = NULL;
-        if (argc == 3) {
-                subdev_name = argv[2];
-        }
+        char *subdev_name = argv[2];
 
         double find_start = get_time();
 
         // First find the device
-        MPDevice *device = mp_device_find(video_name);
+        MPDevice *device = mp_device_find(video_name, subdev_name);
         if (!device) {
                 printf("Device not found\n");
                 return 1;
@@ -73,50 +69,46 @@ main(int argc, char *argv[])
         }
 
         int subdev_fd = -1;
-        if (subdev_name) {
-                const struct media_v2_entity *entity =
-                        mp_device_find_entity(device, subdev_name);
-                if (!entity) {
-                        printf("Unable to find sub-device\n");
-                        return 1;
-                }
+        const struct media_v2_entity *entity =
+                mp_device_find_entity(device, subdev_name);
+        if (!entity) {
+                printf("Unable to find sub-device\n");
+                return 1;
+        }
 
-                const struct media_v2_pad *source_pad =
-                        mp_device_get_pad_from_entity(device, entity->id);
-                const struct media_v2_pad *sink_pad =
-                        mp_device_get_pad_from_entity(device, video_entity_id);
-
-                // Disable other links
-                const struct media_v2_entity *entities =
-                        mp_device_get_entities(device);
-                for (int i = 0; i < mp_device_get_num_entities(device); ++i) {
-                        if (entities[i].id != video_entity_id &&
-                            entities[i].id != entity->id) {
-                                const struct media_v2_pad *pad =
-                                        mp_device_get_pad_from_entity(
-                                                device, entities[i].id);
-                                mp_device_setup_link(
-                                        device, pad->id, sink_pad->id, false);
-                        }
+        const struct media_v2_pad *source_pad =
+                mp_device_get_pad_from_entity(device, entity->id);
+        const struct media_v2_pad *sink_pad =
+                mp_device_get_pad_from_entity(device, video_entity_id);
+
+        // Disable other links
+        const struct media_v2_entity *entities = mp_device_get_entities(device);
+        for (int i = 0; i < mp_device_get_num_entities(device); ++i) {
+                if (entities[i].id != video_entity_id &&
+                    entities[i].id != entity->id) {
+                        const struct media_v2_pad *pad =
+                                mp_device_get_pad_from_entity(device,
+                                                              entities[i].id);
+                        mp_device_setup_link(device, pad->id, sink_pad->id, false);
                 }
+        }
 
-                // Then enable ours
-                mp_device_setup_link(device, source_pad->id, sink_pad->id, true);
+        // Then enable ours
+        mp_device_setup_link(device, source_pad->id, sink_pad->id, true);
 
-                const struct media_v2_interface *iface =
-                        mp_device_find_entity_interface(device, entity->id);
+        const struct media_v2_interface *iface =
+                mp_device_find_entity_interface(device, entity->id);
 
-                char buf[256];
-                if (!mp_find_device_path(iface->devnode, buf, 256)) {
-                        printf("Unable to find sub-device path\n");
-                        return 1;
-                }
+        char buf[256];
+        if (!mp_find_device_path(iface->devnode, buf, 256)) {
+                printf("Unable to find sub-device path\n");
+                return 1;
+        }
 
-                subdev_fd = open(buf, O_RDWR);
-                if (subdev_fd == -1) {
-                        printf("Unable to open sub-device\n");
-                        return 1;
-                }
+        subdev_fd = open(buf, O_RDWR);
+        if (subdev_fd == -1) {
+                printf("Unable to open sub-device\n");
+                return 1;
         }
 
         double open_end = get_time();