src/gallium/winsys/i915/drm/i915_drm_fence.c

   1
   2 #include "i915_drm_winsys.h"
   3 #include "util/u_memory.h"
   4 #include "util/u_atomic.h"
   5 #include "util/u_inlines.h"
   6
   7 /**
   8  * Because gem does not have fence's we have to create our own fences.
   9  *
  10  * They work by keeping the batchbuffer around and checking if that has
  11  * been idled. If bo is NULL fence has expired.
  12  */
  13 struct i915_drm_fence
  14 {
  15    struct pipe_reference reference;
  16    drm_intel_bo *bo;
  17 };
  18
  19
  20 struct pipe_fence_handle *
  21 i915_drm_fence_create(drm_intel_bo *bo)
  22 {
  23    struct i915_drm_fence *fence = CALLOC_STRUCT(i915_drm_fence);
  24
  25    pipe_reference_init(&fence->reference, 1);
  26    /* bo is null if fence already expired */
  27    if (bo) {
  28       drm_intel_bo_reference(bo);
  29       fence->bo = bo;
  30    }
  31
  32    return (struct pipe_fence_handle *)fence;
  33 }
  34
  35 static void
  36 i915_drm_fence_reference(struct i915_winsys *iws,
  37                           struct pipe_fence_handle **ptr,
  38                           struct pipe_fence_handle *fence)
  39 {
  40    struct i915_drm_fence *old = (struct i915_drm_fence *)*ptr;
  41    struct i915_drm_fence *f = (struct i915_drm_fence *)fence;
  42
  43    if (pipe_reference(&((struct i915_drm_fence *)(*ptr))->reference, &f->reference)) {
  44       if (old->bo)
  45          drm_intel_bo_unreference(old->bo);
  46       FREE(old);
  47    }
  48    *ptr = fence;
  49 }
  50
  51 static int
  52 i915_drm_fence_signalled(struct i915_winsys *iws,
  53                           struct pipe_fence_handle *fence)
  54 {
  55    struct i915_drm_fence *f = (struct i915_drm_fence *)fence;
  56
  57    /* fence already expired */
  58    if (!f->bo)
  59            return 1;
  60
  61    return !drm_intel_bo_busy(f->bo);
  62 }
  63
  64 static int
  65 i915_drm_fence_finish(struct i915_winsys *iws,
  66                        struct pipe_fence_handle *fence)
  67 {
  68    struct i915_drm_fence *f = (struct i915_drm_fence *)fence;
  69
  70    /* fence already expired */
  71    if (!f->bo)
  72       return 0;
  73
  74    drm_intel_bo_wait_rendering(f->bo);
  75    drm_intel_bo_unreference(f->bo);
  76    f->bo = NULL;
  77
  78    return 0;
  79 }
  80
  81 void
  82 i915_drm_winsys_init_fence_functions(struct i915_drm_winsys *idws)
  83 {
  84    idws->base.fence_reference = i915_drm_fence_reference;
  85    idws->base.fence_signalled = i915_drm_fence_signalled;
  86    idws->base.fence_finish = i915_drm_fence_finish;
  87 }