[Intel-gfx] [PATCH] drm/i915: Mention when we enable the Ironlake iommu workarounds

[Chris Wilson]

The iommu and gfx on Ironlake do not like each other and require a
big hammer to prevent hard machine hangs. In

commit 5c0422878fcdc279ae9a8e8b66972a15b5efb67f
Author: Ben Widawsky <ben at bwidawsk.net>
Date:   Mon Oct 17 15:51:55 2011 -0700

    drm/i915: ILK + VT-d workaround

we added the workaround, but never emitted any debug message that it was
active. Doing so should help identify known performance regressions.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 998f9a0b322a..2adfef0fa6ac 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1727,6 +1727,9 @@ static int i915_gmch_probe(struct drm_device *dev,
 	dev_priv->gtt.do_idle_maps = needs_idle_maps(dev_priv->dev);
 	dev_priv->gtt.base.clear_range = i915_ggtt_clear_range;
 
+	if (unlikely(dev_priv->gtt.do_idle_maps))
+		DRM_INFO("applying Ironlake quirks for intel_iommu\n");
+
 	return 0;
 }
 
-- 
1.8.5.2