From f8f2ac9a76b0f80a6763ca316116a7bab8486997 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 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 Cc: stable@vger.kernel.org Signed-off-by: Ben Widawsky Signed-off-by: Daniel Vetter --- 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 7637824c6a7d..64c1be0a9cfd 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -527,6 +527,9 @@ # 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 d69f8f49beb5..b3b4b6cea8b0 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3474,6 +3474,11 @@ 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) -- 2.20.1