In function meye_probe() at drivers/media/pci/meye/meye.c:1592, the call to video_register_device() in line 1748 may return a negative error code, and thus function meye_probe() will return the value of variable ret. And, the function meye_probe() will return 0 at last when it runs well. However, when the call to video_register_device() in line 1748 return a negative error code, the value of ret is 0. So the function meye_probe() will return 0 to its caller functions when it runs error because of the failing call to video_register_device(), leading to a wrong return value of function meye_probe().
The related code snippets in meye_probe() is as following.
meye_probe @@ drivers/media/pci/meye/meye.c:1592
1592static int meye_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
1593{
            ...
1672        if ((ret = pci_enable_device(meye.mchip_dev))) {
1673                v4l2_err(v4l2_dev, "meye: pci_enable_device failed\n");
1674                goto outenabledev;
1675        }
            ...
1748        if (video_register_device(meye.vdev, VFL_TYPE_GRABBER,
1749                                  video_nr) < 0) {
1750                v4l2_err(v4l2_dev, "video_register_device failed\n");
1751                goto outvideoreg;
1752        }
            ...
1761outvideoreg:
            ...
1781outnotdev:
1782        return ret;
1783}

Generally, when the call to video_register_device() fails, the return value of caller functions should be different from another return value set when the call to video_register_device() succeeds, like the following codes in another file.
cx8800_initdev @@ drivers/media/pci/cx88/cx88-video.c:1300
1300static int cx8800_initdev(struct pci_dev *pci_dev,
1301                          const struct pci_device_id *pci_id)
1302{
            ...
1493        err = video_register_device(dev->video_dev,VFL_TYPE_GRABBER,
1494                                    video_nr[core->nr]);
1495        if (err < 0) {
1496                printk(KERN_ERR "%s/0: can't register video device\n",
1497                       core->name);
1498                goto fail_unreg;
1499        }
            ...
1545fail_unreg:
1546        cx8800_unregister_video(dev);
1547        free_irq(pci_dev->irq, dev);
1548        mutex_unlock(&core->lock);
1549fail_core:
1550        vb2_dma_sg_cleanup_ctx(dev->alloc_ctx);
1551        core->v4ldev = NULL;
1552        cx88_core_put(core,dev->pci);
1553fail_free:
1554        kfree(dev);
1555        return err;
1556}

Thank you

RUC_Soft_Sec