In the following sequence:
- transfer_map(buffer, DISCARD) // use staging upload
- memcpy(...)
- transfer_unmap
- draw
- transfer_map(buffer, UNSYNCHRONIZED) // non-staging upload
- memcpy(...)
- draw
Currently the order of operations is:
- map#1 - staging buffer
- memcpy to staging buffer
- map#2
- memcpy to buffer
- staging buffer copy to real buffer
- draw#1
- draw#2
When the 2nd map operation doesn't use UNSYNCHRONIZED, the tc_sync_msg() call
will make sure that the bo is unused before mapping it.
But, if it does use UNSYNCHRONIZED and the mapped intervals overlap this commit
clears the UNSYNCHRONIZED to make sure ordering is maintained.
This will affect performance, but correct output is better than fast output.
See https://gitlab.freedesktop.org/mesa/mesa/-/issues/3611.
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7098>
Pierre-Eric Pelloux-Prayer
2900f82e19