i965: Enable resource streamer for the batchbuffer

Check first if the hardware and kernel supports resource streamer. If this
is allowed, tell the kernel to enable the resource streamer enable bit on
MI_BATCHBUFFER_START by specifying I915_EXEC_RESOURCE_STREAMER
execbuffer flags.

v2: - Use new I915_PARAM_HAS_RESOURCE_STREAMER ioctl to check if kernel
      supports RS (Ken).
    - Add brw_device_info::has_resource_streamer and toggle it for
      Haswell, Broadwell, Cherryview, Skylake, and Broxton (Ken).
v3: - Update I915_PARAM_HAS_RESOURCE_STREAMER to match updated kernel.
v4: - Always inspect the getparam.value (Chris Wilson).
v5: - Fold redundant devinfo->has_resource_streamer check in context create
      into init screen.

Cc: kenneth@whitecape.org
Cc: chris@chris-wilson.co.uk
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

src/mesa/drivers/dri/i965/brw_context.c

@@ -871,6 +871,10 @@ brwCreateContext(gl_api api,
 
    brw->predicate.state = BRW_PREDICATE_STATE_RENDER;
 
+   brw->use_resource_streamer = screen->has_resource_streamer &&
+      (brw_env_var_as_boolean("INTEL_USE_HW_BT", false) ||
+       brw_env_var_as_boolean("INTEL_USE_GATHER", false));
+
    ctx->VertexProgram._MaintainTnlProgram = true;
    ctx->FragmentProgram._MaintainTexEnvProgram = true;
 

src/mesa/drivers/dri/i965/brw_context.h

@@ -1134,6 +1134,7 @@ struct brw_context
    bool has_pln;
    bool no_simd8;
    bool use_rep_send;
+   bool use_resource_streamer;
 
    /**
     * Some versions of Gen hardware don't do centroid interpolation correctly

src/mesa/drivers/dri/i965/brw_device_info.c

@@ -170,7 +170,8 @@ static const struct brw_device_info brw_device_info_byt = {
 #define HSW_FEATURES             \
    GEN7_FEATURES,                \
    .is_haswell = true,           \
-   .supports_simd16_3src = true
+   .supports_simd16_3src = true, \
+   .has_resource_streamer = true
 
 static const struct brw_device_info brw_device_info_hsw_gt1 = {
    HSW_FEATURES, .gt = 1,
@@ -229,6 +230,7 @@ static const struct brw_device_info brw_device_info_hsw_gt3 = {
 #define GEN8_FEATURES                               \
    .gen = 8,                                        \
    .has_hiz_and_separate_stencil = true,            \
+   .has_resource_streamer = true,                   \
    .must_use_separate_stencil = true,               \
    .has_llc = true,                                 \
    .has_pln = true,                                 \
@@ -301,6 +303,7 @@ static const struct brw_device_info brw_device_info_chv = {
 #define GEN9_FEATURES                               \
    .gen = 9,                                        \
    .has_hiz_and_separate_stencil = true,            \
+   .has_resource_streamer = true,                   \
    .must_use_separate_stencil = true,               \
    .has_llc = true,                                 \
    .has_pln = true,                                 \

src/mesa/drivers/dri/i965/brw_device_info.h

@@ -46,6 +46,7 @@ struct brw_device_info
    bool has_compr4;
    bool has_surface_tile_offset;
    bool supports_simd16_3src;
+   bool has_resource_streamer;
 
    /**
     * Quirks:

src/mesa/drivers/dri/i965/intel_batchbuffer.c

@@ -279,6 +279,11 @@ throttle(struct brw_context *brw)
    }
 }
 
+/* Drop when RS headers get pulled to libdrm */
+#ifndef I915_EXEC_RESOURCE_STREAMER
+#define I915_EXEC_RESOURCE_STREAMER (1<<15)
+#endif
+
 /* TODO: Push this whole function into bufmgr.
  */
 static int
@@ -305,7 +310,8 @@ do_flush_locked(struct brw_context *brw)
       if (brw->gen >= 6 && batch->ring == BLT_RING) {
          flags = I915_EXEC_BLT;
       } else {
-         flags = I915_EXEC_RENDER;
+         flags = I915_EXEC_RENDER |
+            (brw->use_resource_streamer ? I915_EXEC_RESOURCE_STREAMER : 0);
       }
       if (batch->needs_sol_reset)
 	 flags |= I915_EXEC_GEN7_SOL_RESET;

src/mesa/drivers/dri/i965/intel_screen.c

@@ -1348,6 +1348,11 @@ brw_get_revision(int fd)
    return revision;
 }
 
+/* Drop when RS headers get pulled to libdrm */
+#ifndef I915_PARAM_HAS_RESOURCE_STREAMER
+#define I915_PARAM_HAS_RESOURCE_STREAMER 36
+#endif
+
 /**
  * This is the driver specific part of the createNewScreen entry point.
  * Called when using DRI2.
@@ -1440,6 +1445,15 @@ __DRIconfig **intelInitScreen2(__DRIscreen *psp)
    intelScreen->compiler = brw_compiler_create(intelScreen,
                                                intelScreen->devinfo);
 
+   if (intelScreen->devinfo->has_resource_streamer) {
+      int val = -1;
+      getparam.param = I915_PARAM_HAS_RESOURCE_STREAMER;
+      getparam.value = &val;
+
+      drmIoctl(psp->fd, DRM_IOCTL_I915_GETPARAM, &getparam);
+      intelScreen->has_resource_streamer = val > 0;
+   }
+
    return (const __DRIconfig**) intel_screen_make_configs(psp);
 }
 

src/mesa/drivers/dri/i965/intel_screen.h

@@ -54,6 +54,11 @@ struct intel_screen
 
    bool hw_has_timestamp;
 
+   /**
+    * Does the kernel support resource streamer?
+    */
+   bool has_resource_streamer;
+
    /**
     * Does the kernel support context reset notifications?
     */