Does gbm_bo_map() implicitly synchronise?

I'm experimenting with DRI3 and its use of GBM to share buffers. It 
mostly works fine, but I'm seeing some issues that have me concerned 
there might be a synchronisation issue.

The documentation isn't entirely clear, so my question is if 
gbm_bo_map() handles all the implicit synchronisation for me, or if 
there is something more I can do?

I tried doing gbm_bo_get_fd() followed by a select() and 
ioctl(DMA_BUF_IOCTL_SYNC), but my issue did not go away. Now I'm unsure 
if I'm doing it wrong, or if I'm chasing the wrong theory.

Anyone with insight on what's needed for stable synchronisation?

Regards,
-- 
Pierre Ossman           Software Development
Cendio AB               https://cendio.com
Teknikringen 8          https://twitter.com/ThinLinc
583 30 Linköping        https://facebook.com/ThinLinc
Phone: +46-13-214600

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?