[PATCH 2/2] drm/fbdev: Ensure that one of the probe functions is defined

[Dave Stevenson <dave.stevenson@raspberrypi.com>]

Commit 5d08c44e47b9 ("drm/fbdev: Add memory-agnostic fbdev client")
added the newer probe function, but left a path where no probe
function was called. fb_helper->fb would then be NULL and the strcpy
would throw a NULL pointer exception.

Handle that error case.

Fixes: 5d08c44e47b9 ("drm/fbdev: Add memory-agnostic fbdev client")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index d5e8994345bb..9c8868d7b9d3 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1635,6 +1635,8 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
 		ret = dev->driver->fbdev_probe(fb_helper, &sizes);
 	else if (fb_helper->funcs)
 		ret = fb_helper->funcs->fb_probe(fb_helper, &sizes);
+	else
+		ret = -EINVAL;
 	if (ret < 0)
 		return ret;
 

-- 
2.34.1