From: Ville Syrjälä Date: Thu, 5 Dec 2013 13:51:37 +0000 (+0200) Subject: drm/i915: Disable LP1+ watermarks safely in init X-Git-Tag: firefly_0821_release~176^2~4523^2~16^2~42 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=017636cc09e2c58bc493cc1fe74d858f50d173af;p=firefly-linux-kernel-4.4.55.git drm/i915: Disable LP1+ watermarks safely in init ILK doesn't like if we just write the LP1+ watermarks registers with 0. We need to just disable the watermarks by clearing the enable bit. Use that method also when disabling LP1+ watermarks in init_clock_gating. It looks like disabling the sprite LP1 watermarks can cause underruns even if we just toggle the WM1S_LP_EN bit. So treat that bit like the actual watermark numbers and avoid setting it to 0 immediately. Signed-off-by: Ville Syrjälä Reviewed-by: Imre Deak Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 276e98df1c0d..e321fbc28a0b 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5051,6 +5051,20 @@ static void g4x_disable_trickle_feed(struct drm_device *dev) } } +static void ilk_init_lp_watermarks(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + + I915_WRITE(WM3_LP_ILK, I915_READ(WM3_LP_ILK) & ~WM1_LP_SR_EN); + I915_WRITE(WM2_LP_ILK, I915_READ(WM2_LP_ILK) & ~WM1_LP_SR_EN); + I915_WRITE(WM1_LP_ILK, I915_READ(WM1_LP_ILK) & ~WM1_LP_SR_EN); + + /* + * Don't touch WM1S_LP_EN here. + * Doing so could cause underruns. + */ +} + static void ironlake_init_clock_gating(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; @@ -5084,9 +5098,8 @@ static void ironlake_init_clock_gating(struct drm_device *dev) I915_WRITE(DISP_ARB_CTL, (I915_READ(DISP_ARB_CTL) | DISP_FBC_WM_DIS)); - I915_WRITE(WM3_LP_ILK, 0); - I915_WRITE(WM2_LP_ILK, 0); - I915_WRITE(WM1_LP_ILK, 0); + + ilk_init_lp_watermarks(dev); /* * Based on the document from hardware guys the following bits @@ -5193,9 +5206,7 @@ static void gen6_init_clock_gating(struct drm_device *dev) I915_WRITE(GEN6_GT_MODE, _MASKED_BIT_ENABLE(GEN6_TD_FOUR_ROW_DISPATCH_DISABLE)); - I915_WRITE(WM3_LP_ILK, 0); - I915_WRITE(WM2_LP_ILK, 0); - I915_WRITE(WM1_LP_ILK, 0); + ilk_init_lp_watermarks(dev); I915_WRITE(CACHE_MODE_0, _MASKED_BIT_DISABLE(CM0_STC_EVICT_DISABLE_LRA_SNB)); @@ -5369,9 +5380,7 @@ static void haswell_init_clock_gating(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; - I915_WRITE(WM3_LP_ILK, 0); - I915_WRITE(WM2_LP_ILK, 0); - I915_WRITE(WM1_LP_ILK, 0); + ilk_init_lp_watermarks(dev); /* According to the spec, bit 13 (RCZUNIT) must be set on IVB. * This implements the WaDisableRCZUnitClockGating:hsw workaround. @@ -5420,9 +5429,7 @@ static void ivybridge_init_clock_gating(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; uint32_t snpcr; - I915_WRITE(WM3_LP_ILK, 0); - I915_WRITE(WM2_LP_ILK, 0); - I915_WRITE(WM1_LP_ILK, 0); + ilk_init_lp_watermarks(dev); I915_WRITE(ILK_DSPCLK_GATE_D, ILK_VRHUNIT_CLOCK_GATE_DISABLE);