From 86ebb015fa744dd1e265c9b45ade870ac859a4d5 Mon Sep 17 00:00:00 2001 From: Rodrigo Vivi Date: Tue, 29 Aug 2017 16:07:51 -0700 Subject: [PATCH] drm/i915/cnl: WaDisableI2mCycleOnWRPort On CNL B0 stepping GAM is not able to detect some deadlock condition and then rise the rise the gam_coh_flush. WA database and spec both mentions to set 4AB8[24]=1 as workaround. Although register offset 0x4AB8 is not documented for any platform. References: HSD#1945815, BSID#1112 Cc: Mika Kuoppala Signed-off-by: Rodrigo Vivi Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20170829230751.21047-1-rodrigo.vivi@intel.com --- drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_engine_cs.c | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 1ad22a824921..c718c2f2eaeb 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2373,6 +2373,7 @@ enum i915_power_well_id { #define GAMT_CHKN_BIT_REG _MMIO(0x4ab8) #define GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING (1<<28) +#define GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT (1<<24) #if 0 #define PRB0_TAIL _MMIO(0x2030) diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 4b9b7828802d..ae668340620e 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -1070,6 +1070,11 @@ static int cnl_init_workarounds(struct intel_engine_cs *engine) struct drm_i915_private *dev_priv = engine->i915; int ret; + /* WaDisableI2mCycleOnWRPort: cnl (pre-prod) */ + if (IS_CNL_REVID(dev_priv, CNL_REVID_B0, CNL_REVID_B0)) + WA_SET_BIT(GAMT_CHKN_BIT_REG, + GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT); + /* WaForceContextSaveRestoreNonCoherent:cnl */ WA_SET_BIT_MASKED(CNL_HDC_CHICKEN0, HDC_FORCE_CONTEXT_SAVE_RESTORE_NON_COHERENT); -- 2.30.2