From 4e3c51cbd8a2240a1d18fedad142b9c2ed9573fb Mon Sep 17 00:00:00 2001
From: Emma Anholt <emma@anholt.net>
Date: Tue, 7 Jun 2022 11:31:03 -0700
Subject: [PATCH] freedreno/a5xx: Set the buffer bit appropriately in
 XS_CTRL_REG0.

This seems to be how the bit gets used, from grepping my blob traces.
Hopefully this helps stabilize some stuff.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17004>
---
 src/freedreno/registers/adreno/a5xx.xml          |  4 +++-
 src/gallium/drivers/freedreno/a5xx/fd5_compute.c |  3 ++-
 src/gallium/drivers/freedreno/a5xx/fd5_program.c | 12 ++++++++++--
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/freedreno/registers/adreno/a5xx.xml b/src/freedreno/registers/adreno/a5xx.xml
index 536fcafc94e..010f62e9d82 100644
--- a/src/freedreno/registers/adreno/a5xx.xml
+++ b/src/freedreno/registers/adreno/a5xx.xml
@@ -2463,7 +2463,9 @@ bit 7 for RECTLIST (clear) when z32s8 (used for clear of depth32?  not set
 		<bitfield name="INSTRLEN" low="1" high="31" type="uint"/>
 	</bitset>
 	<bitset name="a5xx_sp_xs_ctrl_reg0" inline="yes">
-		<!-- bit1 + bit2 set for "buffer" mode (ie. shader small enough to fit internally) -->
+		<!-- bit1 almost always set -->
+		<!-- set for "buffer mode" (ie. shader small enough to fit internally) -->
+		<bitfield name="BUFFER" pos="2" type="boolean"/>
 		<!-- 24 or more (full size) GPRS and blob uses TWO_QUADS instead of FOUR_QUADS -->
 		<bitfield name="THREADSIZE" pos="3" type="a3xx_threadsize"/>
 		<bitfield name="HALFREGFOOTPRINT" low="4" high="9" type="uint"/>
diff --git a/src/gallium/drivers/freedreno/a5xx/fd5_compute.c b/src/gallium/drivers/freedreno/a5xx/fd5_compute.c
index 6f236c1f48c..d98b173e9b1 100644
--- a/src/gallium/drivers/freedreno/a5xx/fd5_compute.c
+++ b/src/gallium/drivers/freedreno/a5xx/fd5_compute.c
@@ -60,7 +60,8 @@ cs_program_emit(struct fd_ringbuffer *ring, struct ir3_shader_variant *v)
                A5XX_SP_CS_CTRL_REG0_HALFREGFOOTPRINT(i->max_half_reg + 1) |
                A5XX_SP_CS_CTRL_REG0_FULLREGFOOTPRINT(i->max_reg + 1) |
                A5XX_SP_CS_CTRL_REG0_BRANCHSTACK(ir3_shader_branchstack_hw(v)) |
-               0x6 /* XXX */);
+               COND(instrlen != 0, A5XX_SP_CS_CTRL_REG0_BUFFER) |
+               0x2 /* XXX */);
 
    OUT_PKT4(ring, REG_A5XX_HLSQ_CS_CONFIG, 1);
    OUT_RING(ring, A5XX_HLSQ_CS_CONFIG_CONSTOBJECTOFFSET(0) |
diff --git a/src/gallium/drivers/freedreno/a5xx/fd5_program.c b/src/gallium/drivers/freedreno/a5xx/fd5_program.c
index 2b7fb722ac2..28c310576f6 100644
--- a/src/gallium/drivers/freedreno/a5xx/fd5_program.c
+++ b/src/gallium/drivers/freedreno/a5xx/fd5_program.c
@@ -381,7 +381,14 @@ fd5_program_emit(struct fd_context *ctx, struct fd_ringbuffer *ring,
       ring,
       A5XX_SP_VS_CTRL_REG0_HALFREGFOOTPRINT(s[VS].i->max_half_reg + 1) |
          A5XX_SP_VS_CTRL_REG0_FULLREGFOOTPRINT(s[VS].i->max_reg + 1) |
-         0x6 | /* XXX seems to be always set? */
+         COND(s[VS].instrlen != 0, A5XX_SP_VS_CTRL_REG0_BUFFER) |
+         /* XXX: 0x2 is only unset in
+          * dEQP-GLES3.functional.ubo.single_nested_struct_array.single_buffer.packed_instance_array_vertex
+          * on a collection of blob traces.  That shader is 1091 instrs, 0
+          * half, 3 full, 108 constlen.  Other >1091 instr non-VS shaders don't
+          * unset it, so that's not the trick.
+          */
+         0x2 |
          A5XX_SP_VS_CTRL_REG0_BRANCHSTACK(ir3_shader_branchstack_hw(s[VS].v)) |
          COND(s[VS].v->need_pixlod, A5XX_SP_VS_CTRL_REG0_PIXLODENABLE));
 
@@ -531,7 +538,8 @@ fd5_program_emit(struct fd_context *ctx, struct fd_ringbuffer *ring,
    OUT_RING(
       ring,
       COND(s[FS].v->total_in > 0, A5XX_SP_FS_CTRL_REG0_VARYING) |
-         0x40006 | /* XXX set pretty much everywhere */
+         0x40002 | /* XXX set pretty much everywhere */
+         COND(s[FS].instrlen != 0, A5XX_SP_FS_CTRL_REG0_BUFFER) |
          A5XX_SP_FS_CTRL_REG0_THREADSIZE(fssz) |
          A5XX_SP_FS_CTRL_REG0_HALFREGFOOTPRINT(s[FS].i->max_half_reg + 1) |
          A5XX_SP_FS_CTRL_REG0_FULLREGFOOTPRINT(s[FS].i->max_reg + 1) |