From f282448c74b64f0149d44ceb1a4bea5c7d19384b Mon Sep 17 00:00:00 2001
From: Matt Roper <matthew.d.roper@intel.com>
Date: Tue, 18 Apr 2023 16:02:47 -0700
Subject: [PATCH] drm/xe: Drop GFX_FLSH_CNTL_GEN6 write during GGTT
invalidation
The write of GFX_FLSH_CNTL_GEN6 was inherited from the i915 codebase
where it was used to force a flush of the write-combine buffer in cases
where the GSM/GGTT were mapped as WC. Since Xe never uses WC mappings
of the GGTT, this register write is unnecessary. Furthermore, this
register was removed on Xe_HP-based platforms, so this write winds up
clobbering an unrelated register.
v2:
- Also drop GFX_FLSH_CNTL_GEN6 from the register file now that it's no
longer used. (Lucas)
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230418230247.3802438-1-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
drivers/gpu/drm/xe/regs/xe_gt_regs.h | 3 ---
drivers/gpu/drm/xe/xe_ggtt.c | 5 -----
2 files changed, 8 deletions(-)
diff --git a/drivers/gpu/drm/xe/regs/xe_gt_regs.h b/drivers/gpu/drm/xe/regs/xe_gt_regs.h
index f174758d8307..0a948395acf8 100644
--- a/drivers/gpu/drm/xe/regs/xe_gt_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_gt_regs.h
@@ -351,9 +351,6 @@
#define GEN6_GT_GFX_RC6_LOCKED _MMIO(0x138104)
#define GEN6_GT_GFX_RC6 _MMIO(0x138108)
-#define GFX_FLSH_CNTL_GEN6 _MMIO(0x101008)
-#define GFX_FLSH_CNTL_EN (1 << 0)
-
#define GT_INTR_DW(x) _MMIO(0x190018 + ((x) * 4))
#define GUC_SG_INTR_ENABLE _MMIO(0x190038)
diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
index 0ae373b604f6..531c685cf2a1 100644
--- a/drivers/gpu/drm/xe/xe_ggtt.c
+++ b/drivers/gpu/drm/xe/xe_ggtt.c
@@ -196,11 +196,6 @@ void xe_ggtt_invalidate(struct xe_gt *gt)
{
/* TODO: vfunc for GuC vs. non-GuC */
- /* TODO: i915 makes comments about this being uncached and
- * therefore flushing WC buffers. Is that really true here?
- */
- xe_mmio_write32(gt, GFX_FLSH_CNTL_GEN6.reg, GFX_FLSH_CNTL_EN);
-
if (gt->uc.guc.submission_state.enabled) {
int seqno;
--
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