From 63801f211c6eeb6def635ceee39d165e00fd6e09 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Thu, 12 Dec 2013 17:26:03 -0800 Subject: [PATCH] drm/i915/bdw: Force all Data Cache Data Port access to be Non-Coherent I stumbled on to some unimplemented errata. To be honest, I am not really sure of the impact, just that the docs say to do. No w/a name for this one. v2: v1 was a stale thing which should have never seen the light of day. (Haihao) Cc: Kenneth Graunke Signed-off-by: Ben Widawsky Reviewed-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_reg.h | 4 ++++ drivers/gpu/drm/i915/intel_pm.c | 8 ++++++++ 2 files changed, 12 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index e8cc27cd9494..3259e83eb2c6 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -4167,6 +4167,10 @@ #define GEN7_L3SQCREG4 0xb034 #define L3SQ_URB_READ_CAM_MATCH_DISABLE (1<<27) +/* GEN8 chicken */ +#define HDC_CHICKEN0 0x7300 +#define HDC_FORCE_NON_COHERENT (1<<4) + /* WaCatErrorRejectionIssue */ #define GEN7_SQ_CHICKEN_MBCUNIT_CONFIG 0x9030 #define GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB (1<<11) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index c68abf718825..791fbe386b7c 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5269,6 +5269,14 @@ static void gen8_init_clock_gating(struct drm_device *dev) I915_READ(CHICKEN_PIPESL_1(i) | DPRS_MASK_VBLANK_SRD)); } + + /* Use Force Non-Coherent whenever executing a 3D context. This is a + * workaround for for a possible hang in the unlikely event a TLB + * invalidation occurs during a PSD flush. + */ + I915_WRITE(HDC_CHICKEN0, + I915_READ(HDC_CHICKEN0) | + _MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT)); } static void haswell_init_clock_gating(struct drm_device *dev) -- 2.39.5