5 files changed, 52 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 3f7b20392e26..18746e6cb129 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -778,6 +778,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
         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 2a653cc80395..aac1bf332f75 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -258,6 +258,7 @@ typedef struct drm_i915_private {
         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 5a0fbe59dd5b..c79c0b62ef60 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3735,6 +3735,8 @@ i915_gem_load(struct drm_device *dev)
                 }
         }
 
+        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 fda0dc858a1f..61129e6759eb 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -957,7 +957,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
         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 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                 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 a2776e2807a4..0039f1f97ad8 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -289,6 +289,7 @@ typedef struct drm_i915_irq_wait {
 #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 @@ struct drm_i915_gem_execbuffer2 {
 #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;