drm/i915/cnl: WaRsUseTimeoutMode

Apparently RC6 residency is lower than expected
with EI mode for most of the cases on CNL A0, B0 and C0.

This Wa doesn't solve our lower residency, but I
believe it is better to have it since EI is not
expected to work by HW engineers anyways.

Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170822235828.18322-1-rodrigo.vivi@intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c7b2ca6..d619361 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3077,6 +3077,7 @@ intel_info(const struct drm_i915_private *dev_priv)
 
 #define CNL_REVID_A0           0x0
 #define CNL_REVID_B0           0x1
+#define CNL_REVID_C0           0x2
 
 #define IS_CNL_REVID(p, since, until) \
        (IS_CANNONLAKE(p) && IS_REVID(p, since, until))

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2fcff97..ac4cf98 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6591,7 +6591,7 @@ static void gen9_enable_rc6(struct drm_i915_private *dev_priv)
 {
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
-       uint32_t rc6_mask = 0;
+       u32 rc6_mode, rc6_mask = 0;
 
        /* 1a: Software RC state - RC0 */
        I915_WRITE(GEN6_RC_STATE, 0);
@@ -6629,8 +6629,15 @@ static void gen9_enable_rc6(struct drm_i915_private *dev_priv)
                rc6_mask = GEN6_RC_CTL_RC6_ENABLE;
        DRM_INFO("RC6 %s\n", onoff(rc6_mask & GEN6_RC_CTL_RC6_ENABLE));
        I915_WRITE(GEN6_RC6_THRESHOLD, 37500); /* 37.5/125ms per EI */
+
+       /* WaRsUseTimeoutMode:cnl (pre-prod) */
+       if (IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_C0))
+               rc6_mode = GEN7_RC_CTL_TO_MODE;
+       else
+               rc6_mode = GEN6_RC_CTL_EI_MODE(1);
+
        I915_WRITE(GEN6_RC_CONTROL,
-                  GEN6_RC_CTL_HW_ENABLE | GEN6_RC_CTL_EI_MODE(1) | rc6_mask);
+                  GEN6_RC_CTL_HW_ENABLE | rc6_mode | rc6_mask);
 
        /*
         * 3b: Enable Coarse Power Gating only when RC6 is enabled.