drm/i915: Allow the application to choose the constant addressing mode
The relative-to-general state default is useless as it means having to
rewrite the streaming kernels for each batch. Relative-to-surface is
more useful, as that stream usually needs to be rewritten for each
batch. And absolute addressing mode, vital if you start streaming
state, is also only available by adjusting the register...
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index fda0dc8..61129e6 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -957,7 +957,7 @@
struct intel_ring_buffer *ring;
u32 exec_start, exec_len;
u32 seqno;
- int ret, i;
+ int ret, mode, i;
if (!i915_gem_check_execbuffer(args)) {
DRM_ERROR("execbuf with invalid offset/length\n");
@@ -997,6 +997,39 @@
return -EINVAL;
}
+ mode = args->flags & I915_EXEC_CONSTANTS_MASK;
+ switch (mode) {
+ case I915_EXEC_CONSTANTS_REL_GENERAL:
+ case I915_EXEC_CONSTANTS_ABSOLUTE:
+ case I915_EXEC_CONSTANTS_REL_SURFACE:
+ if (ring == &dev_priv->ring[RCS] &&
+ mode != dev_priv->relative_constants_mode) {
+ if (INTEL_INFO(dev)->gen < 4)
+ return -EINVAL;
+
+ if (INTEL_INFO(dev)->gen > 5 &&
+ mode == I915_EXEC_CONSTANTS_REL_SURFACE)
+ return -EINVAL;
+
+ ret = intel_ring_begin(ring, 4);
+ if (ret)
+ return ret;
+
+ intel_ring_emit(ring, MI_NOOP);
+ intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
+ intel_ring_emit(ring, INSTPM);
+ intel_ring_emit(ring,
+ I915_EXEC_CONSTANTS_MASK << 16 | mode);
+ intel_ring_advance(ring);
+
+ dev_priv->relative_constants_mode = mode;
+ }
+ break;
+ default:
+ DRM_ERROR("execbuf with unknown constants: %d\n", mode);
+ return -EINVAL;
+ }
+
if (args->buffer_count < 1) {
DRM_ERROR("execbuf with %d buffers\n", args->buffer_count);
return -EINVAL;