diff --git a/src/freedreno/registers/adreno/a6xx.xml b/src/freedreno/registers/adreno/a6xx.xml
index e65528da4bd..61bc4508fea 100644
--- a/src/freedreno/registers/adreno/a6xx.xml
+++ b/src/freedreno/registers/adreno/a6xx.xml
@@ -3498,11 +3498,22 @@ to upconvert to 32b float internally?
 		<bitfield name="THREADSIZE" pos="20" type="a6xx_threadsize"/>
 		<bitfield name="UNK21" pos="21" type="boolean"/>
 		<bitfield name="VARYING" pos="22" type="boolean"/>
-		<bitfield name="DIFF_FINE" pos="23" type="boolean"/>
+		<bitfield name="LODPIXMASK" pos="23" type="boolean">
+			<doc>
+				Enable ALL helper invocations in a quad. Necessary for
+				fine derivatives and quad subgroup ops.
+			</doc>
+		</bitfield>
 		<!-- note: vk blob uses bit24 -->
 		<bitfield name="UNK24" pos="24" type="boolean"/>
 		<bitfield name="UNK25" pos="25" type="boolean"/>
-		<bitfield name="PIXLODENABLE" pos="26" type="boolean"/>
+		<bitfield name="PIXLODENABLE" pos="26" type="boolean">
+			<doc>
+				Enable helper invocations. Enables 3 out of 4 fragments,
+				because the coarse derivatives only use half of the quad
+				and so one pixel's value is always unused.
+			</doc>
+		</bitfield>
 		<bitfield name="UNK27" pos="27" type="boolean"/>
 		<bitfield name="EARLYPREAMBLE" pos="28" type="boolean"/>
 		<bitfield name="MERGEDREGS" pos="31" type="boolean"/>
diff --git a/src/freedreno/vulkan/tu_pipeline.cc b/src/freedreno/vulkan/tu_pipeline.cc
index 1b24997e151..59d5ca5b8f2 100644
--- a/src/freedreno/vulkan/tu_pipeline.cc
+++ b/src/freedreno/vulkan/tu_pipeline.cc
@@ -496,7 +496,7 @@ tu6_emit_xs(struct tu_cs *cs,
                .branchstack = ir3_shader_branchstack_hw(xs),
                .threadsize = thrsz,
                .varying = xs->total_in != 0,
-               .diff_fine = xs->need_fine_derivatives,
+               .lodpixmask = xs->need_fine_derivatives,
                /* unknown bit, seems unnecessary */
                .unk24 = true,
                .pixlodenable = xs->need_pixlod,
diff --git a/src/gallium/drivers/freedreno/a6xx/fd6_program.cc b/src/gallium/drivers/freedreno/a6xx/fd6_program.cc
index 818e4593331..cbb987c8edf 100644
--- a/src/gallium/drivers/freedreno/a6xx/fd6_program.cc
+++ b/src/gallium/drivers/freedreno/a6xx/fd6_program.cc
@@ -933,7 +933,7 @@ setup_stateobj(struct fd_screen *screen, struct fd_ringbuffer *ring,
       ring,
       A6XX_SP_FS_CTRL_REG0_THREADSIZE(fssz) |
          COND(enable_varyings, A6XX_SP_FS_CTRL_REG0_VARYING) | 0x1000000 |
-         COND(fs->need_fine_derivatives, A6XX_SP_FS_CTRL_REG0_DIFF_FINE) |
+         COND(fs->need_fine_derivatives, A6XX_SP_FS_CTRL_REG0_LODPIXMASK) |
          A6XX_SP_FS_CTRL_REG0_FULLREGFOOTPRINT(fs->info.max_reg + 1) |
          A6XX_SP_FS_CTRL_REG0_HALFREGFOOTPRINT(fs->info.max_half_reg + 1) |
          COND(fs->mergedregs, A6XX_SP_FS_CTRL_REG0_MERGEDREGS) |