From 450174fe9cc6a1fbc357984f2436ca5fd9960c31 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Tue, 3 May 2016 15:54:21 +0300 Subject: [PATCH] drm/i915/chv: Tune L3 SQC credits based on actual latencies MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit While browsing BSpec I bumped into a note saying we need to tune these values based on actual measurements done after initial enabling. I've checked that it indeed improves things on BXT. I haven't checked this on CHV, but here it is if someone wants to give it a go. v2: - Add note about the discrepancy wrt. to the spec in the formula calculating the credit encodings. (Mika, Ville) - Move the WA comment to the new function. (Ville) v3: - Keep the comment about the SQC WA in the caller. (Ville) CC: Ville Syrjälä CC: Mika Kuoppala Signed-off-by: Imre Deak Reviewed-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1462280061-1457-4-git-send-email-imre.deak@intel.com --- drivers/gpu/drm/i915/i915_reg.h | 6 +++++ drivers/gpu/drm/i915/intel_pm.c | 48 ++++++++++++++++++++++----------- 2 files changed, 38 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 543f440a163e..54ce0b105956 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -6091,6 +6091,12 @@ enum skl_disp_power_wells { #define VLV_B0_WA_L3SQCREG1_VALUE 0x00D30000 #define GEN8_L3SQCREG1 _MMIO(0xB100) +/* + * Note that on CHV the following has an off-by-one error wrt. to BSpec. + * Using the formula in BSpec leads to a hang, while the formula here works + * fine and matches the formulas for all other platforms. A BSpec change + * request has been filed to clarify this. + */ #define L3_GENERAL_PRIO_CREDITS(x) (((x) >> 1) << 19) #define L3_HIGH_PRIO_CREDITS(x) (((x) >> 1) << 14) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 6a48f40a00b9..017c431f9363 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -6696,11 +6696,33 @@ static void lpt_suspend_hw(struct drm_device *dev) } } +static void gen8_set_l3sqc_credits(struct drm_i915_private *dev_priv, + int general_prio_credits, + int high_prio_credits) +{ + u32 misccpctl; + + /* WaTempDisableDOPClkGating:bdw */ + misccpctl = I915_READ(GEN7_MISCCPCTL); + I915_WRITE(GEN7_MISCCPCTL, misccpctl & ~GEN7_DOP_CLOCK_GATE_ENABLE); + + I915_WRITE(GEN8_L3SQCREG1, + L3_GENERAL_PRIO_CREDITS(general_prio_credits) | + L3_HIGH_PRIO_CREDITS(high_prio_credits)); + + /* + * Wait at least 100 clocks before re-enabling clock gating. + * See the definition of L3SQCREG1 in BSpec. + */ + POSTING_READ(GEN8_L3SQCREG1); + udelay(1); + I915_WRITE(GEN7_MISCCPCTL, misccpctl); +} + static void broadwell_init_clock_gating(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; enum pipe pipe; - uint32_t misccpctl; ilk_init_lp_watermarks(dev); @@ -6731,21 +6753,8 @@ static void broadwell_init_clock_gating(struct drm_device *dev) I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) | GEN8_SDEUNIT_CLOCK_GATE_DISABLE); - /* - * WaProgramL3SqcReg1Default:bdw - * WaTempDisableDOPClkGating:bdw - */ - misccpctl = I915_READ(GEN7_MISCCPCTL); - I915_WRITE(GEN7_MISCCPCTL, misccpctl & ~GEN7_DOP_CLOCK_GATE_ENABLE); - I915_WRITE(GEN8_L3SQCREG1, L3_GENERAL_PRIO_CREDITS(30) | - L3_HIGH_PRIO_CREDITS(2)); - /* - * Wait at least 100 clocks before re-enabling clock gating. See - * the definition of L3SQCREG1 in BSpec. - */ - POSTING_READ(GEN8_L3SQCREG1); - udelay(1); - I915_WRITE(GEN7_MISCCPCTL, misccpctl); + /* WaProgramL3SqcReg1Default:bdw */ + gen8_set_l3sqc_credits(dev_priv, 30, 2); /* * WaGttCachingOffByDefault:bdw @@ -7015,6 +7024,13 @@ static void cherryview_init_clock_gating(struct drm_device *dev) I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) | GEN8_SDEUNIT_CLOCK_GATE_DISABLE); + /* + * WaProgramL3SqcReg1Default:chv + * See gfxspecs/Related Documents/Performance Guide/ + * 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. -- 2.39.5