On 3/9/22 09:52, Thomas Zimmermann wrote:
[snip]
+struct drm_gem_object *virtio_gpu_create_object_fbdev(struct drm_device *dev,
size_t size)+{
- return ERR_PTR(-ENOSYS);
+}
As mentioned, I believe this should be ERR_PTR(-ENOTSUPP) instead.
I've been wondering about this as well. I finally went with the rules at [1]. All the variants of ENOTOP/ENOTSUPP seem to be for specific use cases, such as a certain feature is not implemented be a specific interface (e.g., sockets for EOPNOTSUPP). ENOSYS is the only general error that indicates that an entire interface is missing. Even though checkpatch.pl warns that it's only for system calls.
Best regards Thomas
[1] https://www.cs.helsinki.fi/linux/linux-kernel/2002-30/1135.html
Thanks for the link. It would be good to have an authoritative guideline about this in the kernel documentation (and make checkpatch.pl aware).