[PATCH 2/2] fbdev-compositor: enumerate framebuffer device using udev

[Sjoerd Simons]

On startup enumerate the available framebuffer devices using udev and
setup an output for each device, unless a specific device is passed with
--device in which case just create one for that device.

Signed-off-by: Sjoerd Simons <sjoerd.simons at collabora.co.uk>
---
 src/compositor-fbdev.c | 80 ++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 65 insertions(+), 15 deletions(-)

diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
index 75ad646..dc77014 100644
--- a/src/compositor-fbdev.c
+++ b/src/compositor-fbdev.c
@@ -450,9 +450,9 @@ fbdev_frame_buffer_destroy(struct fbdev_output *output)
 static void fbdev_output_destroy(struct weston_output *base);
 static void fbdev_output_disable(struct weston_output *base);
 
-static int
+static struct fbdev_output *
 fbdev_output_create(struct fbdev_compositor *compositor,
-                    const char *device)
+                    const char *device, int x)
 {
 	struct fbdev_output *output;
 	struct weston_config_section *section;
@@ -461,11 +461,11 @@ fbdev_output_create(struct fbdev_compositor *compositor,
 	uint32_t config_transform;
 	char *s;
 
-	weston_log("Creating fbdev output.\n");
+	weston_log("Creating fbdev output for %s.\n", device);
 
 	output = zalloc(sizeof *output);
 	if (output == NULL)
-		return -1;
+		return NULL;
 
 	output->compositor = compositor;
 	output->device = device;
@@ -502,7 +502,7 @@ fbdev_output_create(struct fbdev_compositor *compositor,
 	output->base.subpixel = WL_OUTPUT_SUBPIXEL_UNKNOWN;
 	output->base.make = "unknown";
 	output->base.model = output->fb_info.id;
-	output->base.name = strdup("fbdev");
+	output->base.name = strdup(device);
 
 	section = weston_config_get_section(compositor->base.config,
 					    "output", "name",
@@ -514,7 +514,7 @@ fbdev_output_create(struct fbdev_compositor *compositor,
 	free(s);
 
 	weston_output_init(&output->base, &compositor->base,
-	                   0, 0, output->fb_info.width_mm,
+	                   x, 0, output->fb_info.width_mm,
 	                   output->fb_info.height_mm,
 	                   config_transform,
 			   1);
@@ -544,7 +544,7 @@ fbdev_output_create(struct fbdev_compositor *compositor,
 	weston_log_continue(STAMP_SPACE "guessing %d Hz and 96 dpi\n",
 	                    output->mode.refresh / 1000);
 
-	return 0;
+	return output;
 
 out_hw_surface:
 	pixman_image_unref(output->hw_surface);
@@ -554,7 +554,7 @@ out_hw_surface:
 out_free:
 	free(output);
 
-	return -1;
+	return NULL;
 }
 
 static void
@@ -604,7 +604,7 @@ fbdev_output_reenable(struct fbdev_compositor *compositor,
 {
 	struct fbdev_output *output = to_fbdev_output(base);
 	struct fbdev_screeninfo new_screen_info;
-	int fb_fd;
+	int fb_fd, x;
 	const char *device;
 
 	weston_log("Re-enabling fbdev output.\n");
@@ -633,8 +633,9 @@ fbdev_output_reenable(struct fbdev_compositor *compositor,
 		 * the frame buffer X/Y resolution (such as the shadow buffer)
 		 * are re-initialised. */
 		device = output->device;
+		x = pixman_region32_extents(&base->region)->x1;
 		fbdev_output_destroy(base);
-		fbdev_output_create(compositor, device);
+		fbdev_output_create(compositor, device, x);
 
 		return 0;
 	}
@@ -746,6 +747,52 @@ switch_vt_binding(struct weston_seat *seat, uint32_t time, uint32_t key, void *d
 	weston_launcher_activate_vt(compositor->launcher, key - KEY_F1 + 1);
 }
 
+static int
+fbdev_udev_create_outputs(struct fbdev_compositor *compositor)
+{
+	struct udev_enumerate *e;
+	struct udev_list_entry *entry;
+	int ret = -1;
+	int x = 0;
+
+	e = udev_enumerate_new(compositor->udev);
+	udev_enumerate_add_match_subsystem(e, "graphics");
+	udev_enumerate_add_match_sysname(e, "fb[0-9]*");
+
+	udev_enumerate_scan_devices(e);
+
+	udev_list_entry_foreach (entry, udev_enumerate_get_list_entry(e)) {
+		const char *path, *node;
+		struct udev_device *device;
+		struct fbdev_output *output;
+
+		path = udev_list_entry_get_name(entry);
+		device = udev_device_new_from_syspath(compositor->udev, path);
+		if (!device)
+			continue;
+
+		node = udev_device_get_devnode(device);
+
+		output = fbdev_output_create (compositor, node, x);
+
+		if (output == NULL) {
+			ret = -1;
+			goto out;
+		}
+
+		/* Success if there is at least one output */
+		ret = 0;
+
+		/* Offset for the next output */
+		x = pixman_region32_extents(&output->base.region)->x2;
+	}
+
+out:
+	udev_enumerate_unref(e);
+
+	return ret;
+}
+
 static struct weston_compositor *
 fbdev_compositor_create(struct wl_display *display, int *argc, char *argv[],
                         struct weston_config *config,
@@ -819,8 +866,13 @@ fbdev_compositor_create(struct wl_display *display, int *argc, char *argv[],
 		}
 	}
 
-	if (fbdev_output_create(compositor, param->device) < 0)
-		goto out_pixman;
+	if (param->device != NULL) {
+		if (fbdev_output_create(compositor, param->device, 0) == NULL)
+			goto out_pixman;
+	} else {
+		if (fbdev_udev_create_outputs(compositor) < 0)
+			goto out_pixman;
+	}
 
 	udev_input_init(&compositor->input, &compositor->base, compositor->udev, seat_id);
 
@@ -848,11 +900,9 @@ WL_EXPORT struct weston_compositor *
 backend_init(struct wl_display *display, int *argc, char *argv[],
 	     struct weston_config *config)
 {
-	/* TODO: Ideally, available frame buffers should be enumerated using
-	 * udev, rather than passing a device node in as a parameter. */
 	struct fbdev_parameters param = {
 		.tty = 0, /* default to current tty */
-		.device = "/dev/fb0", /* default frame buffer */
+		.device = NULL, /* default frame buffer */
 		.use_gl = 0,
 	};
 
-- 
2.1.4