From 6d50b0650fb46050d883d1b439a8681178cb2326 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 19 May 2015 20:32:57 +0300 Subject: [PATCH] drm/i915: Enable GTT caching on gen8 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit GTT caching was disabled by default on gen8 due to not working with big pages. Some information suggests that it got fixed, but still GTT caching has been left disabled by default. Or could be it just meant that the default was changed to off, and hence the problem got solved. Enable GTT caching in the hopes of some performance increase. Whether or not the big pages issue has been fixed is irrelevant at this stage since we don't use big pages. This gives me a 1-2% improvement in xonotic on my BSW. Haven't tried BDW, but supposedly it has larger TLBs so might not benefit as much. On HSW GTT caching is enabled by default. Signed-off-by: Ville Syrjälä Reviewed-by: Jesse Barnes Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++++ 2 files changed, 15 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 85088a3cf295..607766d0a15d 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1461,6 +1461,8 @@ enum skl_disp_power_wells { #define RING_HWS_PGA(base) ((base)+0x80) #define RING_HWS_PGA_GEN6(base) ((base)+0x2080) +#define HSW_GTT_CACHE_EN 0x4024 +#define GTT_CACHE_EN_ALL 0xF0007FFF #define GEN7_WR_WATERMARK 0x4028 #define GEN7_GFX_PRIO_CTRL 0x402C #define ARB_MODE 0x4030 diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 85ba52bacfea..84809a67fac8 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -6214,6 +6214,13 @@ static void broadwell_init_clock_gating(struct drm_device *dev) I915_WRITE(GEN8_L3SQCREG1, BDW_WA_L3SQCREG1_DEFAULT); I915_WRITE(GEN7_MISCCPCTL, misccpctl); + /* + * WaGttCachingOffByDefault:bdw + * GTT cache may not work with big pages, so if those + * are ever enabled GTT cache may need to be disabled. + */ + I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL); + lpt_init_clock_gating(dev); } @@ -6489,6 +6496,12 @@ static void cherryview_init_clock_gating(struct drm_device *dev) /* WaDisableSDEUnitClockGating:chv */ I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) | GEN8_SDEUNIT_CLOCK_GATE_DISABLE); + + /* + * GTT cache may not work with big pages, so if those + * are ever enabled GTT cache may need to be disabled. + */ + I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL); } static void g4x_init_clock_gating(struct drm_device *dev) -- 2.11.0