turnip: Allocate tess BOs as a function of draw size
To store tess outputs, the HS stg's into two buffers, one for
per-vertex/per-patch output variables (tess_param) and one for
TessLevelInner/Outer (tess_factor). The addresses of these buffers
are uploaded as consts to the HS/DS and the tess_factor iova is
written to REG_A6XX_PC_TESSFACTOR_ADDR. While the sizes of these
buffers are a function of vetex count and patch count, allocation is
relatively straightforward on freedreno- just keep track of the max
required buffer size for the entire batch and allocate before batch
submit.
In Vulkan, however, a given pipeline can be bound multiple times
across any number of command buffers, each drawing with a different
number of vertices. One solution is to track the max buffer size for
the entire command buffer (similar to fd_batch) and on
vkEndCommandBuffer, allocate appropriately sized tess BOs. Since the
tess BOs addresses are emitted as part of the pipeline state setup
(e.g. PKT4 to REG_A6XX_PC_TESSFACTOR_ADDR), we need to create a new
state group independent of a specific pipeline and parameterize its
IB with the command buffer specific tess BO iovas.
Without a larger refactor, the simplest way to do this is just to
emit per-draw call consts and leverage scratch_bo to re-use buffers.
This way we won't have to store and rewrite earlier packets in the
command stream on vkEndCommandBuffer.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5059>
3 files changed
