drm/i915: kill mappable/fenceable disdinction

a00b10c360b35d6431a "Only enforce fence limits inside the GTT" also
added a fenceable/mappable disdinction when binding/pinning buffers.
This only complicates the code with no pratical gain:

- In execbuffer this matters on for g33/pineview, as this is the only
  chip that needs fences and has an unmappable gtt area. But fences
  are only possible in the mappable part of the gtt, so need_fence
  implies need_mappable. And need_mappable is only set independantly
  with relocations which implies (for sane userspace) that the buffer
  is untiled.

- The overlay code is only really used on i8xx, which doesn't have
  unmappable gtt. And it doesn't support tiled buffers, currently.

- For all other buffers it's a bug to pass in a tiled bo.

In short, this disdinction doesn't have any practical gain.

I've also reverted mapping the overlay and context pages as possibly
unmappable. It's not worth being overtly clever here, all the big
gains from unmappable are for execbuf bos.

Also add a comment for a clever optimization that confused me
while reading the original patch by Chris Wilson.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a2cd579eb9b2..77b34942dc91 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1461,8 +1461,7 @@ intel_pin_and_fence_fb_obj(struct drm_device *dev,
                 BUG();
         }
 
-        ret = i915_gem_object_pin(obj, alignment, true,
-                                  obj_priv->tiling_mode);
+        ret = i915_gem_object_pin(obj, alignment, true);
         if (ret)
                 return ret;
 
@@ -4367,7 +4366,7 @@ static int intel_crtc_cursor_set(struct drm_crtc *crtc,
         /* we only need to pin inside GTT if cursor is non-phy */
         mutex_lock(&dev->struct_mutex);
         if (!dev_priv->info->cursor_needs_physical) {
-                ret = i915_gem_object_pin(bo, PAGE_SIZE, true, false);
+                ret = i915_gem_object_pin(bo, PAGE_SIZE, true);
                 if (ret) {
                         DRM_ERROR("failed to pin cursor bo\n");
                         goto fail_locked;
@@ -5531,7 +5530,7 @@ intel_alloc_context_page(struct drm_device *dev)
         }
 
         mutex_lock(&dev->struct_mutex);
-        ret = i915_gem_object_pin(ctx, 4096, false, false);
+        ret = i915_gem_object_pin(ctx, 4096, true);
         if (ret) {
                 DRM_ERROR("failed to pin power context: %d\n", ret);
                 goto err_unref;