drm/i915: Mention when we enable the Ironlake iommu workarounds

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@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@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 056f1f0e2772adca686620f77539af542f54a05b..9e07a864dec0203c7074f24ef3d1257360024d6d 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1438,6 +1438,9 @@ static int i915_gmch_probe(struct drm_device *dev,
        dev_priv->gtt.base.clear_range = i915_ggtt_clear_range;
        dev_priv->gtt.base.insert_entries = i915_ggtt_insert_entries;
 
+       if (unlikely(dev_priv->gtt.do_idle_maps))
+               DRM_INFO("applying Ironlake quirks for intel_iommu\n");
+
        return 0;
 }