[PATCH] drm/xe: Remove 'Force write completion' from MI_STORE_DATA_IMM

[José Roberto de Souza]

In all places the MI_STORE_DATA_IMM are not followed by a read of
the same memory address in the same batch buffer and the posted writes
are flushed with PIPE_CONTROL or MI_FLUSH_DW in xe_ring_ops.c functions
so there is no need to set this register.

This is not a revert because I think it is worthy keep the register
definition and the comment on top of it so future readers don't
get the same wrong conclusion as I did.

Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
Fixes: 1460bb1fef9c ("drm/xe: Force write completion of MI_STORE_DATA_IMM")
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/xe/instructions/xe_mi_commands.h | 4 ++++
 drivers/gpu/drm/xe/xe_migrate.c                  | 9 ++-------
 drivers/gpu/drm/xe/xe_oa.c                       | 1 -
 drivers/gpu/drm/xe/xe_ring_ops.c                 | 6 ++----
 4 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/xe/instructions/xe_mi_commands.h b/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
index f4ee910f09432..8e9884aaa4b8a 100644
--- a/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
+++ b/drivers/gpu/drm/xe/instructions/xe_mi_commands.h
@@ -35,6 +35,10 @@
 
 #define MI_STORE_DATA_IMM			__MI_INSTR(0x20)
 #define   MI_SDI_GGTT				REG_BIT(22)
+/*
+ * PIPE_CONTROL and MI_FLUSH_DW flushes all posted writes, only needed if
+ * written value is read in batch buffer
+ */
 #define   MI_FORCE_WRITE_COMPLETION_CHECK	REG_BIT(10)
 #define   MI_SDI_LEN_DW				GENMASK(9, 0)
 #define   MI_SDI_NUM_DW(x)			REG_FIELD_PREP(MI_SDI_LEN_DW, (x) + 3 - 2)
diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index 8b32fad678782..9b3bcb789eee3 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -581,9 +581,7 @@ static void emit_pte(struct xe_migrate *m,
 	while (ptes) {
 		u32 chunk = min(MAX_PTE_PER_SDI, ptes);
 
-		bb->cs[bb->len++] = MI_STORE_DATA_IMM |
-				    MI_FORCE_WRITE_COMPLETION_CHECK |
-				    MI_SDI_NUM_QW(chunk);
+		bb->cs[bb->len++] = MI_STORE_DATA_IMM | MI_SDI_NUM_QW(chunk);
 		bb->cs[bb->len++] = ofs;
 		bb->cs[bb->len++] = 0;
 
@@ -1225,9 +1223,7 @@ static void write_pgtable(struct xe_tile *tile, struct xe_bb *bb, u64 ppgtt_ofs,
 		if (!(bb->len & 1))
 			bb->cs[bb->len++] = MI_NOOP;
 
-		bb->cs[bb->len++] = MI_STORE_DATA_IMM |
-				    MI_FORCE_WRITE_COMPLETION_CHECK |
-				    MI_SDI_NUM_QW(chunk);
+		bb->cs[bb->len++] = MI_STORE_DATA_IMM | MI_SDI_NUM_QW(chunk);
 		bb->cs[bb->len++] = lower_32_bits(addr);
 		bb->cs[bb->len++] = upper_32_bits(addr);
 		if (pt_op->bind)
@@ -1392,7 +1388,6 @@ __xe_migrate_update_pgtables(struct xe_migrate *m,
 			u32 idx = 0;
 
 			bb->cs[bb->len++] = MI_STORE_DATA_IMM |
-					    MI_FORCE_WRITE_COMPLETION_CHECK |
 					    MI_SDI_NUM_QW(chunk);
 			bb->cs[bb->len++] = ofs;
 			bb->cs[bb->len++] = 0; /* upper_32_bits */
diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
index ae94490b0eac8..6b440a5470255 100644
--- a/drivers/gpu/drm/xe/xe_oa.c
+++ b/drivers/gpu/drm/xe/xe_oa.c
@@ -691,7 +691,6 @@ static void xe_oa_store_flex(struct xe_oa_stream *stream, struct xe_lrc *lrc,
 
 	do {
 		bb->cs[bb->len++] = MI_STORE_DATA_IMM | MI_SDI_GGTT |
-				    MI_FORCE_WRITE_COMPLETION_CHECK |
 				    MI_SDI_NUM_DW(1);
 		bb->cs[bb->len++] = offset + flex->offset * sizeof(u32);
 		bb->cs[bb->len++] = 0;
diff --git a/drivers/gpu/drm/xe/xe_ring_ops.c b/drivers/gpu/drm/xe/xe_ring_ops.c
index 3a75a08b6be92..0be4f489d3e12 100644
--- a/drivers/gpu/drm/xe/xe_ring_ops.c
+++ b/drivers/gpu/drm/xe/xe_ring_ops.c
@@ -72,8 +72,7 @@ static int emit_user_interrupt(u32 *dw, int i)
 
 static int emit_store_imm_ggtt(u32 addr, u32 value, u32 *dw, int i)
 {
-	dw[i++] = MI_STORE_DATA_IMM | MI_SDI_GGTT |
-		  MI_FORCE_WRITE_COMPLETION_CHECK | MI_SDI_NUM_DW(1);
+	dw[i++] = MI_STORE_DATA_IMM | MI_SDI_GGTT | MI_SDI_NUM_DW(1);
 	dw[i++] = addr;
 	dw[i++] = 0;
 	dw[i++] = value;
@@ -163,8 +162,7 @@ static int emit_pipe_invalidate(u32 mask_flags, bool invalidate_tlb, u32 *dw,
 static int emit_store_imm_ppgtt_posted(u64 addr, u64 value,
 				       u32 *dw, int i)
 {
-	dw[i++] = MI_STORE_DATA_IMM | MI_FORCE_WRITE_COMPLETION_CHECK |
-		  MI_SDI_NUM_QW(1);
+	dw[i++] = MI_STORE_DATA_IMM | MI_SDI_NUM_QW(1);
 	dw[i++] = lower_32_bits(addr);
 	dw[i++] = upper_32_bits(addr);
 	dw[i++] = lower_32_bits(value);
-- 
2.47.1