[PATCH] drm/syncobj: add DRM_IOCTL_SYNCOBJ_IMPORT/EXPORT_SYNC_FILE

[Simon Ser]

I had a look at the IGT and I'm not sure about the approach. It seems
like the patch replaces occurrences of the old FLAGS_IMPORT_SYNC_FILE
and FLAGS_EXPORT_SYNC_FILE plus TRANSFER with the new IOCTLs. However
we still want to test the functionality of that old codepath: we need
to continue to test that the old IOCTLs work as expected.

Are the old IOCTLs still sufficiently tested elsewhere? If not, we need
to either duplicate the tests, either add a flag to the test function
to select between old and new.

Also, it would be good to have some basic tests for invalid cases, e.g.
for the invalid zero syncobj handle, for timeline points which haven't
materialized yet, etc.

I wonder if we need to detect at runtime whether the IOCTL is available.
I'm not sure what the IGT requirements are, is it supposed to run on
any Linux version, or does it require drm-next?

It would help to post the IGT patches on the mailing list so that we
can do a proper review there.