drm/i915: Apply a big hammer to 865 GEM object CPU cache flushing.

[mirror_ubuntu-hirsute-kernel.git] / drivers / gpu / drm / i915 / i915_gem.c

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e4408daf8cef099d388611268be5cbd5605c1dc4..e2421869a40cf809f509c57e58a770a7c0e4043a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2423,6 +2423,16 @@ i915_gem_clflush_object(struct drm_gem_object *obj)
        if (obj_priv->pages == NULL)
                return;
 
+       /* XXX: The 865 in particular appears to be weird in how it handles
+        * cache flushing.  We haven't figured it out, but the
+        * clflush+agp_chipset_flush doesn't appear to successfully get the
+        * data visible to the PGU, while wbinvd + agp_chipset_flush does.
+        */
+       if (IS_I865G(obj->dev)) {
+               wbinvd();
+               return;
+       }
+
        drm_clflush_pages(obj_priv->pages, obj->size / PAGE_SIZE);
 }