nvfx: avoid flushes in primitives

Currently we miscalculate the space needed to push vertices, causing
flushes where they should not happen.

Use a much more conservative estimate to fix it.

It will be done better in the future (e.g. using the nv50 primitive
splitter).

diff --git a/src/gallium/drivers/nvfx/nvfx_vbo.c b/src/gallium/drivers/nvfx/nvfx_vbo.c
index b9566f9ee27f0aacb827cb6b11d64e089a33fe39..73f00adff0472a6c50bbe4cb74e30a11688aec7c 100644 (file)
--- a/src/gallium/drivers/nvfx/nvfx_vbo.c
+++ b/src/gallium/drivers/nvfx/nvfx_vbo.c
@@ -195,7 +195,10 @@ nvfx_draw_arrays(struct pipe_context *pipe,
 
                nvfx_state_emit(nvfx);
 
-               vc = nouveau_vbuf_split(AVAIL_RING(chan), 6, 256,
+               unsigned avail = AVAIL_RING(chan);
+               avail -= 16 + (avail >> 10); /* for the BEGIN_RING_NIs, conservatively assuming one every 1024, plus 16 for safety */
+
+               vc = nouveau_vbuf_split(avail, 6, 256,
                                        mode, start, count, &restart);
                if (!vc) {
                        FIRE_RING(chan);
@@ -249,7 +252,10 @@ nvfx_draw_elements_u08(struct nvfx_context *nvfx, void *ib,
 
                nvfx_state_emit(nvfx);
 
-               vc = nouveau_vbuf_split(AVAIL_RING(chan), 6, 2,
+               unsigned avail = AVAIL_RING(chan);
+               avail -= 16 + (avail >> 10); /* for the BEGIN_RING_NIs, conservatively assuming one every 1024, plus 16 for safety */
+
+               vc = nouveau_vbuf_split(avail, 6, 2,
                                        mode, start, count, &restart);
                if (vc == 0) {
                        FIRE_RING(chan);
@@ -300,7 +306,10 @@ nvfx_draw_elements_u16(struct nvfx_context *nvfx, void *ib,
 
                nvfx_state_emit(nvfx);
 
-               vc = nouveau_vbuf_split(AVAIL_RING(chan), 6, 2,
+               unsigned avail = AVAIL_RING(chan);
+               avail -= 16 + (avail >> 10); /* for the BEGIN_RING_NIs, conservatively assuming one every 1024, plus 16 for safety */
+
+               vc = nouveau_vbuf_split(avail, 6, 2,
                                        mode, start, count, &restart);
                if (vc == 0) {
                        FIRE_RING(chan);
@@ -351,7 +360,10 @@ nvfx_draw_elements_u32(struct nvfx_context *nvfx, void *ib,
 
                nvfx_state_emit(nvfx);
 
-               vc = nouveau_vbuf_split(AVAIL_RING(chan), 5, 1,
+               unsigned avail = AVAIL_RING(chan);
+               avail -= 16 + (avail >> 10); /* for the BEGIN_RING_NIs, conservatively assuming one every 1024, plus 16 for safety */
+
+               vc = nouveau_vbuf_split(avail, 5, 1,
                                        mode, start, count, &restart);
                if (vc == 0) {
                        FIRE_RING(chan);
@@ -427,7 +439,10 @@ nvfx_draw_elements_vbo(struct pipe_context *pipe,
 
                nvfx_state_emit(nvfx);
 
-               vc = nouveau_vbuf_split(AVAIL_RING(chan), 6, 256,
+               unsigned avail = AVAIL_RING(chan);
+               avail -= 16 + (avail >> 10); /* for the BEGIN_RING_NIs, conservatively assuming one every 1024, plus 16 for safety */
+
+               vc = nouveau_vbuf_split(avail, 6, 256,
                                        mode, start, count, &restart);
                if (!vc) {
                        FIRE_RING(chan);