drm/radeon: deal with errors from framebuffer init path.

We've been getting occasional oops running a 32-bit kernel on a certain
system in our RHEL test hw. It appears that we fail to get sufficent ioremap
space for the framebuffer, and this leads to an oops.

This patch should fix the oops and leave a message in the logs we can
check for.

A future fix would probably to resize the console to a size that we can
ioremap.

Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/radeon/radeon_display.c

···
 	.create_handle = radeon_user_framebuffer_create_handle,
 };
 
-void
+int
 radeon_framebuffer_init(struct drm_device *dev,
 			struct radeon_framebuffer *rfb,
 			struct drm_mode_fb_cmd2 *mode_cmd,
 			struct drm_gem_object *obj)
 {
+	int ret;
 	rfb->obj = obj;
-	drm_framebuffer_init(dev, &rfb->base, &radeon_fb_funcs);
+	ret = drm_framebuffer_init(dev, &rfb->base, &radeon_fb_funcs);
+	if (ret) {
+		rfb->obj = NULL;
+		return ret;
+	}
 	drm_helper_mode_fill_fb_struct(&rfb->base, mode_cmd);
+	return 0;
 }
 
 static struct drm_framebuffer *
···
 {
 	struct drm_gem_object *obj;
 	struct radeon_framebuffer *radeon_fb;
+	int ret;
 
 	obj = drm_gem_object_lookup(dev, file_priv, mode_cmd->handles[0]);
 	if (obj ==  NULL) {
···
 	if (radeon_fb == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	radeon_framebuffer_init(dev, radeon_fb, mode_cmd, obj);
+	ret = radeon_framebuffer_init(dev, radeon_fb, mode_cmd, obj);
+	if (ret) {
+		kfree(radeon_fb);
+		drm_gem_object_unreference_unlocked(obj);
+		return NULL;
+	}
 
 	return &radeon_fb->base;
 }

drivers/gpu/drm/radeon/radeon_fb.c

···
 							  sizes->surface_depth);
 
 	ret = radeonfb_create_pinned_object(rfbdev, &mode_cmd, &gobj);
+	if (ret) {
+		DRM_ERROR("failed to create fbcon object %d\n", ret);
+		return ret;
+	}
+
 	rbo = gem_to_radeon_bo(gobj);
 
 	/* okay we have an object now allocate the framebuffer */
···
 
 	info->par = rfbdev;
 
-	radeon_framebuffer_init(rdev->ddev, &rfbdev->rfb, &mode_cmd, gobj);
+	ret = radeon_framebuffer_init(rdev->ddev, &rfbdev->rfb, &mode_cmd, gobj);
+	if (ret) {
+		DRM_ERROR("failed to initalise framebuffer %d\n", ret);
+		goto out_unref;
+	}
 
 	fb = &rfbdev->rfb.base;
 

drivers/gpu/drm/radeon/radeon_mode.h

···
 				     u16 blue, int regno);
 extern void radeon_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 				     u16 *blue, int regno);
-void radeon_framebuffer_init(struct drm_device *dev,
+int radeon_framebuffer_init(struct drm_device *dev,
 			     struct radeon_framebuffer *rfb,
 			     struct drm_mode_fb_cmd2 *mode_cmd,
 			     struct drm_gem_object *obj);