[Intel-gfx] [PATCH 13/23] drm/i915/kbl: Add WaDisableDynamicCreditSharing

[Mika Kuoppala]

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 at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h         | 2 ++
 drivers/gpu/drm/i915/intel_ringbuffer.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 14e0ec818ea4..e0441da08201 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1672,6 +1672,8 @@ enum skl_disp_power_wells {
 
 #define GEN7_TLB_RD_ADDR	_MMIO(0x4700)
 
+#define GAMT_CHKN_BIT_REG	_MMIO(0x4ab8)
+
 #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 64922ae9bd69..402e0feb4cca 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1188,6 +1188,10 @@ static int kbl_init_workarounds(struct intel_engine_cs *engine)
 	if (ret)
 		return ret;
 
+	/* WaDisableDynamicCreditSharing:kbl */
+	if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
+		WA_SET_BIT(GAMT_CHKN_BIT_REG, (1 << 28));
+
 	/* WaDisableFenceDestinationToSLM:kbl (pre-prod) */
 	if (IS_KBL_REVID(dev_priv, KBL_REVID_A0, KBL_REVID_A0))
 		WA_SET_BIT_MASKED(HDC_CHICKEN0,
-- 
2.5.0