[PATCH] intel: allow fence register tracking to be disable

[Daniel Vetter <daniel.vetter@ffwll.ch>]

libdrm just doesn't know enough to do this precisely. Therefore allow
this to be disabled and put the burden on the client where enough
information is available.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 intel/intel_bufmgr.h     |    1 +
 intel/intel_bufmgr_gem.c |   25 ++++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/intel/intel_bufmgr.h b/intel/intel_bufmgr.h
index 0984ab0..4e3dd20 100644
--- a/intel/intel_bufmgr.h
+++ b/intel/intel_bufmgr.h
@@ -135,6 +135,7 @@ drm_intel_bo *drm_intel_bo_gem_create_from_name(drm_intel_bufmgr *bufmgr,
 						unsigned int handle);
 void drm_intel_bufmgr_gem_enable_reuse(drm_intel_bufmgr *bufmgr);
 void drm_intel_bufmgr_gem_enable_fenced_relocs(drm_intel_bufmgr *bufmgr);
+int drm_intel_bufmgr_gem_disable_fence_accounting(drm_intel_bufmgr *bufmgr);
 int drm_intel_gem_bo_map_gtt(drm_intel_bo *bo);
 int drm_intel_gem_bo_unmap_gtt(drm_intel_bo *bo);
 void drm_intel_gem_bo_start_gtt_access(drm_intel_bo *bo, int write_enable);
diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index a2cf6e6..b7aa2bd 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -101,6 +101,7 @@ typedef struct _drm_intel_bufmgr_gem {
 	int gen;
 	char bo_reuse;
 	char fenced_relocs;
+	char no_fence_accounting;
 } drm_intel_bufmgr_gem;
 
 #define DRM_INTEL_RELOC_FENCE (1<<0)
@@ -1737,6 +1738,28 @@ drm_intel_bufmgr_gem_enable_fenced_relocs(drm_intel_bufmgr *bufmgr)
 }
 
 /**
+ * Disable the fence checking in drm_intel_gem_bo_get_aperture_space
+ *
+ * The gem buffer manager doesn't know which tiled buffers need fence registers
+ * and which do not. The checking done in get_aperture_space is therefore
+ * necessarily much too pessimistic. Enabling this option allows the client to
+ * check fence register usage on its own.
+ *
+ * Returns 0 if unfenced relocations are not available, i.e. the user has to
+ * reserve a fence for every relocation of a tiled buffer. Returns 1 if unfenced
+ * relocations are available.
+ */
+int drm_intel_bufmgr_gem_disable_fence_accounting(drm_intel_bufmgr *bufmgr)
+{
+	drm_intel_bufmgr_gem *bufmgr_gem = (drm_intel_bufmgr_gem *)bufmgr;
+
+	if (bufmgr_gem->fenced_relocs)
+		bufmgr_gem->no_fence_accounting = 1;
+
+	return bufmgr_gem->fenced_relocs;
+}
+
+/**
  * Return the additional aperture space required by the tree of buffer objects
  * rooted at bo.
  */
@@ -1884,7 +1907,7 @@ drm_intel_gem_check_aperture_space(drm_intel_bo **bo_array, int count)
 	int total_fences;
 
 	/* Check for fence reg constraints if necessary */
-	if (bufmgr_gem->available_fences) {
+	if (bufmgr_gem->available_fences && !bufmgr_gem->no_fence_accounting) {
 		total_fences = drm_intel_gem_total_fences(bo_array, count);
 		if (total_fences > bufmgr_gem->available_fences)
 			return -ENOSPC;
-- 
1.7.0.4