From b7884eb45ec98c0d34c7f49005ae9d4b4b4e38f6 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Mon, 4 Jun 2012 11:18:15 +0200 Subject: drm/i915: hold forcewake around ring hw init Empirical evidence suggests that we need to: On at least one ivb machine when running the hangman i-g-t test, the rings don't properly initialize properly - the RING_START registers seems to be stuck at all zeros. Holding forcewake around this register init sequences makes chip reset reliable again. Note that this is not the first such issue: commit f01db988ef6f6c70a6cc36ee71e4a98a68901229 Author: Sean Paul Date: Fri Mar 16 12:43:22 2012 -0400 drm/i915: Add wait_for in init_ring_common added delay loops to make RING_START and RING_CTL initialization reliable on the blt ring at boot-up. So I guess it won't hurt if we do this unconditionally for all force_wake needing gpus. To avoid copy&pasting of the HAS_FORCE_WAKE check I've added a new intel_info bit for that. v2: Fixup missing commas in static struct and properly handling the error case in init_ring_common, both noticed by Jani Nikula. Cc: stable@vger.kernel.org Reported-and-tested-by: Yang Guang Reviewed-by: Eugeni Dodonov Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50522 Signed-Off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_ringbuffer.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_ringbuffer.c') diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 9fbad086cb4b..e5b84ff89ca5 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -266,10 +266,15 @@ u32 intel_ring_get_active_head(struct intel_ring_buffer *ring) static int init_ring_common(struct intel_ring_buffer *ring) { - drm_i915_private_t *dev_priv = ring->dev->dev_private; + struct drm_device *dev = ring->dev; + drm_i915_private_t *dev_priv = dev->dev_private; struct drm_i915_gem_object *obj = ring->obj; + int ret = 0; u32 head; + if (HAS_FORCE_WAKE(dev)) + gen6_gt_force_wake_get(dev_priv); + /* Stop the ring if it's running. */ I915_WRITE_CTL(ring, 0); I915_WRITE_HEAD(ring, 0); @@ -317,7 +322,8 @@ static int init_ring_common(struct intel_ring_buffer *ring) I915_READ_HEAD(ring), I915_READ_TAIL(ring), I915_READ_START(ring)); - return -EIO; + ret = -EIO; + goto out; } if (!drm_core_check_feature(ring->dev, DRIVER_MODESET)) @@ -329,7 +335,11 @@ static int init_ring_common(struct intel_ring_buffer *ring) ring->last_retired_head = -1; } - return 0; +out: + if (HAS_FORCE_WAKE(dev)) + gen6_gt_force_wake_put(dev_priv); + + return ret; } static int -- cgit v1.2.3