On Tue, 2017-07-25 at 11:10 +0100, Lionel Landwerlin wrote: > Cool, got it :) > > Reviewed-by: Lionel Landwerlin <lionel.g.landwer...@intel.com>
Thanks! > I think we might want this in stable right? Yes, this and the first patch in the series too. I'll make sure to add the CC when I push them. > On 25/07/17 09:30, Iago Toral wrote: > > On Tue, 2017-07-25 at 00:46 +0100, Lionel Landwerlin wrote: > > > On 21/07/17 09:26, Iago Toral Quiroga wrote: > > > > We were exposing 31 because the hardware allows for 33 and we > > > > need > > > > to reserve one vertex buffer to upload > > > > VertexIndex/InstanceIndex > > > > and > > > > another to upload DrawID when needed, however, there is another > > > > restriction in the hardware regarding the size of the VUE > > > > entries > > > > that limits this down to 30 (28 after VertexIndex and DrawID): > > > > > > Something's weird here in the description from the PRMs (sorry, > > > not > > > your > > > fault). > > > EU limit of 128 GRFs should allow 32 vertex elements of 4 GRFs. > > > Looking at the PRMs, it seems the limits arises from the maximum > > > value > > > allowed in "Vertex URB Entry Read Length" in SIMD8, which is 15. > > > And 15 * 8 = 120 gives us a limit to 30 vertex elements. > > > > > > Is that a fair description? > > > > Yeah, I copied the description from the PRMs but you are right, the > > limit comes from the vertex urb entry size. I'll update the commit > > log. > > Thanks! > > > > > > Than > > > > From 3DSTATE_VS, Vertex URB entry read length: > > > > > > > > "For SIMD8 dispatch, each vertex element requires 4 GRFs of > > > > payload data, therefore the number of GRFs with vertex > > > > data > > > > will > > > > be 8 times the value programmed in this field. The EU > > > > limit of > > > > 128 > > > > GRFs imposes a maximum limit of 30 elements per vertex > > > > pushed > > > > into > > > > the payload, though the pactical limit may be lower." > > > > > > > > There is an assertion in place to check that we don't exceed > > > > this > > > > limit > > > > and that is triggered when we expose more than 28 attributes > > > > and we > > > > have > > > > shaders that use more than 30 attributes in total (including > > > > VertexIndex/InstanceIndex and DrawID). > > > > --- > > > > src/intel/vulkan/anv_private.h | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/src/intel/vulkan/anv_private.h > > > > b/src/intel/vulkan/anv_private.h > > > > index 4dce360c76..f83f49b671 100644 > > > > --- a/src/intel/vulkan/anv_private.h > > > > +++ b/src/intel/vulkan/anv_private.h > > > > @@ -89,7 +89,7 @@ struct gen_l3_config; > > > > */ > > > > #define ANV_HZ_FC_VAL 1.0f > > > > > > > > -#define MAX_VBS 31 > > > > +#define MAX_VBS 28 > > > > #define MAX_SETS 8 > > > > #define MAX_RTS 8 > > > > #define MAX_VIEWPORTS 16 > > > > > > > > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
