Bspec states that we need to turn off dynamic credit
sharing on kbl revid a0 and b0. This happens by writing bit 28
on 0x4ab8.
References: HSD#2225601, HSD#2226938, HSD#2225763
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_ringbuffer.c | 5 +++++
2 files changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index b49c39bd8abb..eb9875883379 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1672,6 +1672,9 @@ enum skl_disp_power_wells {
#define GEN7_TLB_RD_ADDR _MMIO(0x4700)
+#define GAMT_CHKN_BIT_REG _MMIO(0x4ab8)
+#define GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING (1<<28)
+
#if 0
#define PRB0_TAIL _MMIO(0x2030)
#define PRB0_HEAD _MMIO(0x2034)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 50379e863ae3..d1c02ed20f37 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1199,6 +1199,11 @@ static int kbl_init_workarounds(struct intel_engine_cs *engine)
I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
GEN9_GAPS_TSV_CREDIT_DISABLE));
+ /* WaDisableDynamicCreditSharing:kbl */
+ if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
+ WA_SET_BIT(GAMT_CHKN_BIT_REG,
+ GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING);
+
/* WaDisableFenceDestinationToSLM:kbl (pre-prod) */
if (IS_KBL_REVID(dev_priv, KBL_REVID_A0, KBL_REVID_A0))
WA_SET_BIT_MASKED(HDC_CHICKEN0,
--
2.7.4
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