From 1b660a0096dec5739c0ac5148e7aeead04056d87 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Wed, 3 Oct 2012 19:34:24 -0700 Subject: [PATCH] drm/i915: Fix GT_MODE default value commit f8f2ac9a76b0f80a6763ca316116a7bab8486997 upstream. I can't even find how I figured this might be needed anymore. But sure enough, the value I'm reading back on platforms doesn't match what the docs recommends. It seemed to fix Chris' GT1 in limited testing as well. Tested-by: Chris Wilson Signed-off-by: Ben Widawsky Signed-off-by: Daniel Vetter Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_reg.h | 3 +++ drivers/gpu/drm/i915/intel_pm.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 48d5e8e051cf6..4cad9088d1fdd 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -514,6 +514,9 @@ # define VS_TIMER_DISPATCH (1 << 6) # define MI_FLUSH_ENABLE (1 << 12) +#define GEN6_GT_MODE 0x20d0 +#define GEN6_GT_MODE_HI (1 << 9) + #define GFX_MODE 0x02520 #define GFX_MODE_GEN7 0x0229c #define RING_MODE_GEN7(ring) ((ring)->mmio_base+0x29c) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index a48c391bb9368..b55aa0e7997a7 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3363,6 +3363,11 @@ static void gen6_init_clock_gating(struct drm_device *dev) DISPPLANE_TRICKLE_FEED_DISABLE); intel_flush_display_plane(dev_priv, pipe); } + + /* The default value should be 0x200 according to docs, but the two + * platforms I checked have a 0 for this. (Maybe BIOS overrides?) */ + I915_WRITE(GEN6_GT_MODE, _MASKED_BIT_DISABLE(0xffff)); + I915_WRITE(GEN6_GT_MODE, _MASKED_BIT_ENABLE(GEN6_GT_MODE_HI)); } static void gen7_setup_fixed_func_scheduler(struct drm_i915_private *dev_priv) -- 2.47.2