• Tvrtko Ursulin's avatar
    drm/i915: Infrastructure for supporting different GGTT views per object · fe14d5f4
    Tvrtko Ursulin authored
    Things like reliable GGTT mappings and mirrored 2d-on-3d display will need
    to map objects into the same address space multiple times.
    
    Added a GGTT view concept and linked it with the VMA to distinguish between
    multiple instances per address space.
    
    New objects and GEM functions which do not take this new view as a parameter
    assume the default of zero (I915_GGTT_VIEW_NORMAL) which preserves the
    previous behaviour.
    
    This now means that objects can have multiple VMA entries so the code which
    assumed there will only be one also had to be modified.
    
    Alternative GGTT views are supposed to borrow DMA addresses from obj->pages
    which is DMA mapped on first VMA instantiation and unmapped on the last one
    going away.
    
    v2:
        * Removed per view special casing in i915_gem_ggtt_prepare /
          finish_object in favour of creating and destroying DMA mappings
          on first VMA instantiation and last VMA destruction. (Daniel Vetter)
        * Simplified i915_vma_unbind which does not need to count the GGTT views.
          (Daniel Vetter)
        * Also moved obj->map_and_fenceable reset under the same check.
        * Checkpatch cleanups.
    
    v3:
        * Only retire objects once the last VMA is unbound.
    
    v4:
        * Keep scatter-gather table for alternative views persistent for the
          lifetime of the VMA.
        * Propagate binding errors to callers and handle appropriately.
    
    v5:
        * Explicitly look for normal GGTT view in i915_gem_obj_bound to align
          usage in i915_gem_object_ggtt_unpin. (Michel Thierry)
        * Change to single if statement in i915_gem_obj_to_ggtt. (Michel Thierry)
        * Removed stray semi-colon in i915_gem_object_set_cache_level.
    
    For: VIZ-4544
    Signed-off-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Reviewed-by: default avatarMichel Thierry <michel.thierry@intel.com>
    [danvet: Drop hunk from i915_gem_shrink since it's just prettification
    but upsets a __must_check warning.]
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    fe14d5f4
i915_drv.h 94.9 KB