drm/vkms: Add mode_config initialization

Initialize minimum and maximum width and height of the frame buffers
with default values.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/75c55df671f24b037f9172700b479f4bb2fa7c92.1526514457.git.rodrigosiqueiramelo@gmail.com

drivers/gpu/drm/vkms/vkms_drv.c

@@ -9,6 +9,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_atomic_helper.h>
 #include "vkms_drv.h"
 
 #define DRIVER_NAME	"vkms"
@@ -17,6 +18,12 @@
 #define DRIVER_MAJOR	1
 #define DRIVER_MINOR	0
 
+#define XRES_MIN    32
+#define YRES_MIN    32
+
+#define XRES_MAX  8192
+#define YRES_MAX  8192
+
 static struct vkms_device *vkms_device;
 
 static const struct file_operations vkms_driver_fops = {
@@ -67,6 +74,11 @@ static const struct drm_connector_funcs vkms_connector_funcs = {
 	.destroy = vkms_connector_destroy,
 };
 
+static const struct drm_mode_config_funcs vkms_mode_funcs = {
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
 static int __init vkms_init(void)
 {
 	int ret;
@@ -87,6 +99,11 @@ static int __init vkms_init(void)
 	}
 
 	drm_mode_config_init(&vkms_device->drm);
+	vkms_device->drm.mode_config.funcs = &vkms_mode_funcs;
+	vkms_device->drm.mode_config.min_width = XRES_MIN;
+	vkms_device->drm.mode_config.min_height = YRES_MIN;
+	vkms_device->drm.mode_config.max_width = XRES_MAX;
+	vkms_device->drm.mode_config.max_height = YRES_MAX;
 
 	ret = drm_connector_init(&vkms_device->drm, &vkms_device->connector,
 				 &vkms_connector_funcs,