When you set shadows to Ultra in the recently released open source game,
Tesseract, the game will segfault with the following:

radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
radeon: Failed to allocate a buffer:
radeon:    size      : 536870912 bytes
radeon:    alignment : 32768 bytes
radeon:    domains   : 4
failed allocating shadow atlas!

MSAA also seems to hang the entire machine