From 1feb7864b2cbd874a677ce04d61834d5664133ab Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Fri, 9 Aug 2019 20:34:55 +0100 Subject: [PATCH] drm/i915/gtt: enable GTT cache by default For some platforms the GTT cache is by default not enabled, and currently where we explicitly enable it, we make it conditional on 2M GTT page support, since the BSpec states that we must disable it if we enable 2M/1G pages. To make this more consistent opt for blanket enabling the GTT cache for all relevant gens in a single place, while still keeping the same behaviour of checking for 2M support. BSpec: 9314 BSpec: 423 Signed-off-by: Matthew Auld Cc: Joonas Lahtinen Cc: Chris Wilson Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20190809193456.3836-1-matthew.auld@intel.com --- drivers/gpu/drm/i915/i915_gem_gtt.c | 21 +++++++++++++++++++++ drivers/gpu/drm/i915/intel_pm.c | 12 ------------ 2 files changed, 21 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 83a02e7..72a227c 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -2035,6 +2035,27 @@ static void gtt_write_workarounds(struct intel_gt *gt) GEN8_GAMW_ECO_DEV_RW_IA, 0, GAMW_ECO_ENABLE_64K_IPS_FIELD); + + if (IS_GEN_RANGE(i915, 8, 11)) { + bool can_use_gtt_cache = true; + + /* + * According to the BSpec if we use 2M/1G pages then we also + * need to disable the GTT cache. At least on BDW we can see + * visual corruption when using 2M pages, and not disabling the + * GTT cache. + */ + if (HAS_PAGE_SIZES(i915, I915_GTT_PAGE_SIZE_2M)) + can_use_gtt_cache = false; + + /* WaGttCachingOffByDefault */ + intel_uncore_write(uncore, + HSW_GTT_CACHE_EN, + can_use_gtt_cache ? GTT_CACHE_EN_ALL : 0); + WARN_ON_ONCE(can_use_gtt_cache && + intel_uncore_read(uncore, + HSW_GTT_CACHE_EN) == 0); + } } int i915_ppgtt_init_hw(struct intel_gt *gt) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 780df8d..aca676e 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -9169,9 +9169,6 @@ static void skl_init_clock_gating(struct drm_i915_private *dev_priv) static void bdw_init_clock_gating(struct drm_i915_private *dev_priv) { - /* The GTT cache must be disabled if the system is using 2M pages. */ - bool can_use_gtt_cache = !HAS_PAGE_SIZES(dev_priv, - I915_GTT_PAGE_SIZE_2M); enum pipe pipe; /* WaSwitchSolVfFArbitrationPriority:bdw */ @@ -9204,9 +9201,6 @@ static void bdw_init_clock_gating(struct drm_i915_private *dev_priv) /* WaProgramL3SqcReg1Default:bdw */ gen8_set_l3sqc_credits(dev_priv, 30, 2); - /* WaGttCachingOffByDefault:bdw */ - I915_WRITE(HSW_GTT_CACHE_EN, can_use_gtt_cache ? GTT_CACHE_EN_ALL : 0); - /* WaKVMNotificationOnConfigChange:bdw */ I915_WRITE(CHICKEN_PAR2_1, I915_READ(CHICKEN_PAR2_1) | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT); @@ -9471,12 +9465,6 @@ static void chv_init_clock_gating(struct drm_i915_private *dev_priv) * LSQC Setting Recommendations. */ gen8_set_l3sqc_credits(dev_priv, 38, 2); - - /* - * 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_i915_private *dev_priv) -- 2.7.4