On Mon, Jul 30, 2012 at 12:03 PM, Alex Deucher <alexdeuc...@gmail.com> wrote: > On Mon, Jul 30, 2012 at 11:48 AM, Marek Olšák <mar...@gmail.com> wrote: >> On Mon, Jul 30, 2012 at 4:56 PM, Jerome Glisse <j.gli...@gmail.com> wrote: >>> On Sun, Jul 29, 2012 at 1:04 PM, Marek Olšák <mar...@gmail.com> wrote: >>>> If we don't need stencil, don't allocate it. >>>> If we need only stencil (like PIPE_FORMAT_S8_UINT), don't allocate depth. >>>> >>>> v2: actually do it correctly >>> >>> Big NAK >>> >>> We need to allocate stencil and depth no matter what. Otherwise it >>> will lockup. You can take a look by poisonning the surface and see >>> that when stencil is disabled or depth is disabled the hw still write >>> to it. >> >> :) >> >> If what you say is true, then we're in a big trouble. Regardless of >> this patch, we're in it right now, because we cannot fully disable >> depth or stencil if the user binds a NULL zbuffer. That's clearly the >> kind of issue that cannot be fixed in the allocator code and should be >> fixed in r600g where the hardware is programmed. >> >> I *think* that the correct way to disable Z or stencil is to set the >> Z_INVALID or STENCIL_INVALID format, respectively, and not by >> disabling reads and writes. (cc'ing Alex to confirm that if he can). I >> don't think the hardware designers have added those "invalid" formats >> just for the lulz. Please see my latest kernel patch "drm/radeon/kms: >> allow "invalid" DB formats as a means to disable DB" that tries to >> address this issue. > > That is correct. I just verified with the hw team. If you allocate > both buffers there are some restrictions in that they share tiling > parameters, but you can set either buffer to _INVALID and allocate one > or the other independently.
Some further clarifications from the hw team. If you want to have truly independent z and stencil buffers that allows for mixing and matching, you need to make sure that any z and stencil buffer that can be bound together must share the same addressing parameters (except tile split), and you must disable the htile buffer on evergreen and before (DB_Z_INFO.TILE_SURFACE_ENABLE=0) or disable the htile buffer for stencil on cayman and newer (DB_STENCIL_INFO.TILE_STENCIL_DISABLE=1). If you are only interested in unbinding z or stencil independently (but not mixing and matching) then you don't need to the above restrictions on the htile buffer. You can do so by setting the format to INVALID. Alex _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
