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_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 3f7b203..18746e6 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -778,6 +778,9 @@
case I915_PARAM_HAS_COHERENT_RINGS:
value = 1;
break;
+ case I915_PARAM_HAS_EXEC_CONSTANTS:
+ value = INTEL_INFO(dev)->gen >= 4;
+ break;
default:
DRM_DEBUG_DRIVER("Unknown parameter %d\n",
param->param);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2a653cc..aac1bf3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -258,6 +258,7 @@
const struct intel_device_info *info;
int has_gem;
+ int relative_constants_mode;
void __iomem *regs;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5a0fbe5..c79c0b6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3735,6 +3735,8 @@
}
}
+ dev_priv->relative_constants_mode = I915_EXEC_CONSTANTS_REL_GENERAL;
+
/* Old X drivers will take 0-2 for front, back, depth buffers */
if (!drm_core_check_feature(dev, DRIVER_MODESET))
dev_priv->fence_reg_start = 3;
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;
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index a2776e2..0039f1f 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -289,6 +289,7 @@
#define I915_PARAM_HAS_BLT 11
#define I915_PARAM_HAS_RELAXED_FENCING 12
#define I915_PARAM_HAS_COHERENT_RINGS 13
+#define I915_PARAM_HAS_EXEC_CONSTANTS 14
typedef struct drm_i915_getparam {
int param;
@@ -635,6 +636,17 @@
#define I915_EXEC_RENDER (1<<0)
#define I915_EXEC_BSD (2<<0)
#define I915_EXEC_BLT (3<<0)
+
+/* Used for switching the constants addressing mode on gen4+ RENDER ring.
+ * Gen6+ only supports relative addressing to dynamic state (default) and
+ * absolute addressing.
+ *
+ * These flags are ignored for the BSD and BLT rings.
+ */
+#define I915_EXEC_CONSTANTS_MASK (3<<6)
+#define I915_EXEC_CONSTANTS_REL_GENERAL (0<<6) /* default */
+#define I915_EXEC_CONSTANTS_ABSOLUTE (1<<6)
+#define I915_EXEC_CONSTANTS_REL_SURFACE (2<<6) /* gen4/5 only */
__u64 flags;
__u64 rsvd1;
__u64 rsvd2;