drm/i915:bxt: implement WaProgramL3SqcReg1DefaultForPerf

This patch applies a performance enhancement workaround
based on analysis of DX and OCL S-Curve workloads. We
increase the General Priority Credits for L3SQ from the
hardware default of 56 to the max value 62, and decrease
the High Priority credits from 8 to 2.

v2: Only apply to B0 onwards

v3: Move w/a to per engine init, ie bxt_init_workarounds

Signed-off-by: Tim Gore <tim.gore@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461314761-36854-1-git-send-email-tim.gore@intel.com
Reviewed-by: Michel Thierry <michel.thierry@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 58ac6c7..25e229b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6090,6 +6090,7 @@ enum skl_disp_power_wells {
 
 #define GEN8_L3SQCREG1                         _MMIO(0xB100)
 #define  BDW_WA_L3SQCREG1_DEFAULT              0x784000
+#define  BXT_WA_L3SQCREG1_DEFAULT              0xF84000
 
 #define GEN7_L3CNTLREG1                                _MMIO(0xB01C)
 #define  GEN7_WA_FOR_GEN7_L3_CONTROL                   0x3C47FF8C

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 245386e..f6e8e7e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1180,6 +1180,10 @@ static int bxt_init_workarounds(struct intel_engine_cs *engine)
                        return ret;
        }
 
+       /* WaProgramL3SqcReg1DefaultForPerf:bxt */
+       if (IS_BXT_REVID(dev, BXT_REVID_B0, REVID_FOREVER))
+               I915_WRITE(GEN8_L3SQCREG1, BXT_WA_L3SQCREG1_DEFAULT);
+
        return 0;
 }