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drm/i915: hold forcewake around ring hw init

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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 f01db988ef
Author: Sean Paul <seanpaul@chromium.org>
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 <guang.a.yang@intel.com>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50522
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter
2012-06-04 11:18:15 +02:00
parent 3eef8918ff
commit b7884eb45e
3 changed files with 25 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/gpu/drm/i915/intel_ringbuffer.c
View File

@@ -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