From 1038392b4dd02a46006d38f33aab71486d477ced Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Fri, 15 Aug 2014 01:21:54 +0300 Subject: [PATCH] drm/i915: Disable trickle feed for gen2/3 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit My 830 is unhappy with trickle feed enabled. The symptom is that the image on the screen shifts a bit to right occasionally. The BIOS initially disables trickle feed, but it gets reset during suspend, so we need to re-disable it ourselves. Juse disable it always. Also disable it for all other gen2/3 platforms since we disable it for all more recent platforms as well (until HSW that is). At least my 855 doesn't seem to mind us doing this. I don't have gen3 hardware to test that. Signed-off-by: Ville Syrjälä Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_reg.h | 4 ++++ drivers/gpu/drm/i915/intel_pm.c | 10 ++++++++++ 2 files changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 20673cc450c8..b7b2e63c14d0 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1272,6 +1272,10 @@ enum punit_power_well { #define INSTPM_TLB_INVALIDATE (1<<9) #define INSTPM_SYNC_FLUSH (1<<5) #define ACTHD 0x020c8 +#define MEM_MODE 0x020cc +#define MEM_DISPLAY_B_TRICKLE_FEED_DISABLE (1<<3) /* 830 only */ +#define MEM_DISPLAY_A_TRICKLE_FEED_DISABLE (1<<2) /* 830/845 only */ +#define MEM_DISPLAY_TRICKLE_FEED_DISABLE (1<<2) /* 85x only */ #define FW_BLC 0x020d8 #define FW_BLC2 0x020dc #define FW_BLC_SELF 0x020e0 /* 915+ only */ diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 38b61e4d17ae..8541feb893f3 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -6138,6 +6138,9 @@ static void gen3_init_clock_gating(struct drm_device *dev) /* On GEN3 we really need to make sure the ARB C3 LP bit is set */ I915_WRITE(MI_ARB_STATE, _MASKED_BIT_ENABLE(MI_ARB_C3_LP_WRITE_ENABLE)); + + I915_WRITE(MI_ARB_STATE, + _MASKED_BIT_ENABLE(MI_ARB_DISPLAY_TRICKLE_FEED_DISABLE)); } static void i85x_init_clock_gating(struct drm_device *dev) @@ -6149,6 +6152,9 @@ static void i85x_init_clock_gating(struct drm_device *dev) /* interrupts should cause a wake up from C3 */ I915_WRITE(MI_STATE, _MASKED_BIT_ENABLE(MI_AGPBUSY_INT_EN) | _MASKED_BIT_DISABLE(MI_AGPBUSY_830_MODE)); + + I915_WRITE(MEM_MODE, + _MASKED_BIT_ENABLE(MEM_DISPLAY_TRICKLE_FEED_DISABLE)); } static void i830_init_clock_gating(struct drm_device *dev) @@ -6156,6 +6162,10 @@ static void i830_init_clock_gating(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; I915_WRITE(DSPCLK_GATE_D, OVRUNIT_CLOCK_GATE_DISABLE); + + I915_WRITE(MEM_MODE, + _MASKED_BIT_ENABLE(MEM_DISPLAY_A_TRICKLE_FEED_DISABLE) | + _MASKED_BIT_ENABLE(MEM_DISPLAY_B_TRICKLE_FEED_DISABLE)); } void intel_init_clock_gating(struct drm_device *dev) -- 2.20.1