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authorChris Wilson <chris@chris-wilson.co.uk>2012-08-08 10:23:22 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-08-08 14:29:12 +0200
commit2fedbff948cf5bc1e9977b7bc885aae45bd32f74 (patch)
tree2fb434867abb4bff322fd8e34a7ce9039a9e820f /include/drm
parent6c6cf5aa9c583478b19e23149feaa92d01fb8c2d (diff)
drm/i915: Add I915_GEM_PARAM_HAS_SEMAPHORES
Userspace tries to estimate the cost of ring switching based on whether the GPU and GEM supports semaphores. (If we have multiple rings and no semaphores, userspace assumes that the cost of switching rings between batches is exorbitant and will endeavour to keep the next batch on the active ring - as a coarse approximation to tracking both destination and source surfaces.) Currently userspace has to guess whether semaphores exist based on the chipset generation and the module parameter, i915.semaphores. This is a crude and inaccurate guess as the defaults internally depend upon other chipset features being enabled or disabled, nor does it extend well into the future. By exporting a HAS_SEMAPHORES parameter, we can easily query the driver and obtain an accurate answer. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/i915_drm.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 772b0d638912..d8a79bf59ae7 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -311,6 +311,7 @@ typedef struct drm_i915_irq_wait {
#define I915_PARAM_HAS_LLC 17
#define I915_PARAM_HAS_ALIASING_PPGTT 18
#define I915_PARAM_HAS_WAIT_TIMEOUT 19
+#define I915_PARAM_HAS_SEMAPHORES 20
typedef struct drm_i915_getparam {
int param;