Because PPGTT PDEs within the GTT are calculated in cachelines (HW guys consistency ftw) we do a divide which will wreak havoc if this is wrong, and I know that from experience). If/when we move to multiple PPGTTs this will have to become a WARN, and return an error. For now however it should always be considered fatal, and only a developer could hit it. Signed-off-by: Ben Widawsky <ben at bwidawsk.net> --- drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 50df194..0503f09 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -85,6 +85,8 @@ static int gen6_ppgtt_enable(struct drm_device *dev) uint32_t pd_entry; int i; + BUG_ON(ppgtt->pd_offset & 0x3f); + pd_addr = (gen6_gtt_pte_t __iomem*)dev_priv->gtt.gsm + ppgtt->pd_offset / sizeof(gen6_gtt_pte_t); for (i = 0; i < ppgtt->num_pd_entries; i++) { -- 1.8.2.1