i965: Add hardware context support.

With fixes and updates from Ben Widawsky and comments from Paul Berry.

v2: Use drm_intel_gem_context_destroy to destroy hardware context;
    remove useless initialization of hw_ctx, both suggested by Eric.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Acked-by: Paul Berry <stereotype441@gmail.com>

configure.ac

@@ -33,7 +33,7 @@ USER_CXXFLAGS="$CXXFLAGS"
 dnl Versions for external dependencies
 LIBDRM_REQUIRED=2.4.24
 LIBDRM_RADEON_REQUIRED=2.4.31
-LIBDRM_INTEL_REQUIRED=2.4.34
+LIBDRM_INTEL_REQUIRED=2.4.37
 LIBDRM_NVVIEUX_REQUIRED=2.4.33
 LIBDRM_NOUVEAU_REQUIRED=2.4.33
 DRI2PROTO_REQUIRED=2.6

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

@@ -302,6 +302,7 @@ brwCreateContext(int api,
 
    brw->prim_restart.in_progress = false;
    brw->prim_restart.enable_cut_index = false;
+   intel->hw_ctx = drm_intel_gem_context_create(intel->bufmgr);
 
    brw_init_state( brw );
 

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

@@ -80,6 +80,8 @@ static void brw_destroy_context( struct intel_context *intel )
 
    free(brw->curbe.last_buf);
    free(brw->curbe.next_buf);
+
+   drm_intel_gem_context_destroy(intel->hw_ctx);
 }
 
 /**
@@ -166,11 +168,16 @@ static void brw_new_batch( struct intel_context *intel )
 {
    struct brw_context *brw = brw_context(&intel->ctx);
 
-   /* Mark all context state as needing to be re-emitted.
-    * This is probably not as severe as on 915, since almost all of our state
-    * is just in referenced buffers.
+   /* If the kernel supports hardware contexts, then most hardware state is
+    * preserved between batches; we only need to re-emit state that is required
+    * to be in every batch.  Otherwise we need to re-emit all the state that
+    * would otherwise be stored in the context (which for all intents and
+    * purposes means everything).
     */
-   brw->state.dirty.brw |= BRW_NEW_CONTEXT | BRW_NEW_BATCH;
+   if (intel->hw_ctx == NULL)
+      brw->state.dirty.brw |= BRW_NEW_CONTEXT;
+
+   brw->state.dirty.brw |= BRW_NEW_BATCH;
 
    /* Assume that the last command before the start of our batch was a
     * primitive, for safety.

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

@@ -188,8 +188,13 @@ do_flush_locked(struct intel_context *intel)
       if (ret == 0) {
          if (unlikely(INTEL_DEBUG & DEBUG_AUB) && intel->vtbl.annotate_aub)
             intel->vtbl.annotate_aub(intel);
-	 ret = drm_intel_bo_mrb_exec(batch->bo, 4*batch->used, NULL, 0, 0,
-				     flags);
+	 if (intel->hw_ctx == NULL || batch->is_blit) {
+	    ret = drm_intel_bo_mrb_exec(batch->bo, 4 * batch->used, NULL, 0, 0,
+					flags);
+	 } else {
+	    ret = drm_intel_gem_bo_context_exec(batch->bo, intel->hw_ctx,
+						4 * batch->used, flags);
+	 }
       }
    }
 

src/mesa/drivers/dri/intel/intel_context.h

@@ -225,6 +225,8 @@ struct intel_context
 
    int urb_size;
 
+   drm_intel_context *hw_ctx;
+
    struct intel_batchbuffer batch;
 
    drm_intel_bo *first_post_swapbuffers_batch;