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 <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d69f8f4..b3b4b6c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3474,6 +3474,11 @@
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)