/**************************************************************************
 * 
 * Copyright 2003 VMware, Inc.
 * All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 **************************************************************************/



#include "main/glheader.h"
#include "main/mtypes.h"
#include "main/imports.h"
#include "main/macros.h"
#include "main/renderbuffer.h"
#include "main/framebuffer.h"

#include "tnl/tnl.h"
#include "tnl/t_context.h"
#include "tnl/t_vertex.h"
#include "swrast_setup/swrast_setup.h"

#include "intel_batchbuffer.h"
#include "intel_mipmap_tree.h"
#include "intel_regions.h"
#include "intel_tris.h"
#include "intel_fbo.h"
#include "intel_buffers.h"

#include "i915_reg.h"
#include "i915_context.h"

static void
i915_render_prevalidate(struct intel_context *intel)
{
   struct i915_context *i915 = i915_context(&intel->ctx);

   i915ValidateFragmentProgram(i915);
}

static void
i915_render_start(struct intel_context *intel)
{
   intel_prepare_render(intel);
}


static void
i915_reduced_primitive_state(struct intel_context *intel, GLenum rprim)
{
   struct i915_context *i915 = i915_context(&intel->ctx);
   GLuint st1 = i915->state.Stipple[I915_STPREG_ST1];

   st1 &= ~ST1_ENABLE;

   switch (rprim) {
   case GL_QUADS: /* from RASTERIZE(GL_QUADS) in t_dd_tritemp.h */
   case GL_TRIANGLES:
      if (intel->ctx.Polygon.StippleFlag && intel->hw_stipple)
         st1 |= ST1_ENABLE;
      break;
   case GL_LINES:
   case GL_POINTS:
   default:
      break;
   }

   i915->intel.reduced_primitive = rprim;

   if (st1 != i915->state.Stipple[I915_STPREG_ST1]) {
      INTEL_FIREVERTICES(intel);

      I915_STATECHANGE(i915, I915_UPLOAD_STIPPLE);
      i915->state.Stipple[I915_STPREG_ST1] = st1;
   }
}


/* Pull apart the vertex format registers and figure out how large a
 * vertex is supposed to be. 
 */
static bool
i915_check_vertex_size(struct intel_context *intel, GLuint expected)
{
   struct i915_context *i915 = i915_context(&intel->ctx);
   int lis2 = i915->state.Ctx[I915_CTXREG_LIS2];
   int lis4 = i915->state.Ctx[I915_CTXREG_LIS4];
   int i, sz = 0;

   switch (lis4 & S4_VFMT_XYZW_MASK) {
   case S4_VFMT_XY:
      sz = 2;
      break;
   case S4_VFMT_XYZ:
      sz = 3;
      break;
   case S4_VFMT_XYW:
      sz = 3;
      break;
   case S4_VFMT_XYZW:
      sz = 4;
      break;
   default:
      fprintf(stderr, "no xyzw specified\n");
      return 0;
   }

   if (lis4 & S4_VFMT_SPEC_FOG)
      sz++;
   if (lis4 & S4_VFMT_COLOR)
      sz++;
   if (lis4 & S4_VFMT_DEPTH_OFFSET)
      sz++;
   if (lis4 & S4_VFMT_POINT_WIDTH)
      sz++;
   if (lis4 & S4_VFMT_FOG_PARAM)
      sz++;

   for (i = 0; i < 8; i++) {
      switch (lis2 & S2_TEXCOORD_FMT0_MASK) {
      case TEXCOORDFMT_2D:
         sz += 2;
         break;
      case TEXCOORDFMT_3D:
         sz += 3;
         break;
      case TEXCOORDFMT_4D:
         sz += 4;
         break;
      case TEXCOORDFMT_1D:
         sz += 1;
         break;
      case TEXCOORDFMT_2D_16:
         sz += 1;
         break;
      case TEXCOORDFMT_4D_16:
         sz += 2;
         break;
      case TEXCOORDFMT_NOT_PRESENT:
         break;
      default:
         fprintf(stderr, "bad texcoord fmt %d\n", i);
         return false;
      }
      lis2 >>= S2_TEXCOORD_FMT1_SHIFT;
   }

   if (sz != expected)
      fprintf(stderr, "vertex size mismatch %d/%d\n", sz, expected);

   return sz == expected;
}


static void
i915_emit_invarient_state(struct intel_context *intel)
{
   BATCH_LOCALS;

   BEGIN_BATCH(17);

   OUT_BATCH(_3DSTATE_AA_CMD |
             AA_LINE_ECAAR_WIDTH_ENABLE |
             AA_LINE_ECAAR_WIDTH_1_0 |
             AA_LINE_REGION_WIDTH_ENABLE | AA_LINE_REGION_WIDTH_1_0);

   OUT_BATCH(_3DSTATE_DFLT_DIFFUSE_CMD);
   OUT_BATCH(0);

   OUT_BATCH(_3DSTATE_DFLT_SPEC_CMD);
   OUT_BATCH(0);

   OUT_BATCH(_3DSTATE_DFLT_Z_CMD);
   OUT_BATCH(0);

   /* Don't support texture crossbar yet */
   OUT_BATCH(_3DSTATE_COORD_SET_BINDINGS |
             CSB_TCB(0, 0) |
             CSB_TCB(1, 1) |
             CSB_TCB(2, 2) |
             CSB_TCB(3, 3) |
             CSB_TCB(4, 4) | CSB_TCB(5, 5) | CSB_TCB(6, 6) | CSB_TCB(7, 7));

   /* Need to initialize this to zero.
    */
   OUT_BATCH(_3DSTATE_LOAD_STATE_IMMEDIATE_1 | I1_LOAD_S(3) | (0));
   OUT_BATCH(0);

   OUT_BATCH(_3DSTATE_SCISSOR_RECT_0_CMD);
   OUT_BATCH(0);
   OUT_BATCH(0);

   /* XXX: Use this */
   OUT_BATCH(_3DSTATE_SCISSOR_ENABLE_CMD | DISABLE_SCISSOR_RECT);

   OUT_BATCH(_3DSTATE_DEPTH_SUBRECT_DISABLE);

   OUT_BATCH(_3DSTATE_LOAD_INDIRECT | 0);       /* disable indirect state */
   OUT_BATCH(0);

   ADVANCE_BATCH();
}


#define emit(intel, state, size )		     \
   intel_batchbuffer_data(intel, state, size)

static GLuint
get_dirty(struct i915_hw_state *state)
{
   GLuint dirty;

   /* Workaround the multitex hang - if one texture unit state is
    * modified, emit all texture units.
    */
   dirty = state->active & ~state->emitted;
   if (dirty & I915_UPLOAD_TEX_ALL)
      state->emitted &= ~I915_UPLOAD_TEX_ALL;
   dirty = state->active & ~state->emitted;
   return dirty;
}


static GLuint
get_state_size(struct i915_hw_state *state)
{
   GLuint dirty = get_dirty(state);
   GLuint i;
   GLuint sz = 0;

   if (dirty & I915_UPLOAD_INVARIENT)
      sz += 30 * 4;

   if (dirty & I915_UPLOAD_RASTER_RULES)
      sz += sizeof(state->RasterRules);

   if (dirty & I915_UPLOAD_CTX)
      sz += sizeof(state->Ctx);

   if (dirty & I915_UPLOAD_BLEND)
      sz += sizeof(state->Blend);

   if (dirty & I915_UPLOAD_BUFFERS)
      sz += sizeof(state->Buffer);

   if (dirty & I915_UPLOAD_STIPPLE)
      sz += sizeof(state->Stipple);

   if (dirty & I915_UPLOAD_TEX_ALL) {
      int nr = 0;
      for (i = 0; i < I915_TEX_UNITS; i++)
         if (dirty & I915_UPLOAD_TEX(i))
            nr++;

      sz += (2 + nr * 3) * sizeof(GLuint) * 2;
   }

   if (dirty & I915_UPLOAD_CONSTANTS)
      sz += state->ConstantSize * sizeof(GLuint);

   if (dirty & I915_UPLOAD_PROGRAM)
      sz += state->ProgramSize * sizeof(GLuint);

   return sz;
}

/* Push the state into the sarea and/or texture memory.
 */
static void
i915_emit_state(struct intel_context *intel)
{
   struct i915_context *i915 = i915_context(&intel->ctx);
   struct i915_hw_state *state = &i915->state;
   int i, count, aper_count;
   GLuint dirty;
   drm_intel_bo *aper_array[3 + I915_TEX_UNITS];
   GET_CURRENT_CONTEXT(ctx);
   BATCH_LOCALS;

   /* We don't hold the lock at this point, so want to make sure that
    * there won't be a buffer wrap between the state emits and the primitive
    * emit header.
    *
    * It might be better to talk about explicit places where
    * scheduling is allowed, rather than assume that it is whenever a
    * batchbuffer fills up.
    */
   intel_batchbuffer_require_space(intel,
				   get_state_size(state) +
                                   INTEL_PRIM_EMIT_SIZE);
   count = 0;
 again:
   if (intel->batch.bo == NULL) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "i915 emit state");
      assert(0);
   }
   aper_count = 0;
   dirty = get_dirty(state);

   aper_array[aper_count++] = intel->batch.bo;
   if (dirty & I915_UPLOAD_BUFFERS) {
      if (state->draw_region)
	 aper_array[aper_count++] = state->draw_region->bo;
      if (state->depth_region)
	 aper_array[aper_count++] = state->depth_region->bo;
   }

   if (dirty & I915_UPLOAD_TEX_ALL) {
      for (i = 0; i < I915_TEX_UNITS; i++) {
	 if (dirty & I915_UPLOAD_TEX(i)) {
	    if (state->tex_buffer[i]) {
	       aper_array[aper_count++] = state->tex_buffer[i];
	    }
	 }
      }
   }

   if (dri_bufmgr_check_aperture_space(aper_array, aper_count)) {
       if (count == 0) {
	   count++;
	   intel_batchbuffer_flush(intel);
	   goto again;
       } else {
	   _mesa_error(ctx, GL_OUT_OF_MEMORY, "i915 emit state");
	   assert(0);
       }
   }

   /* work out list of buffers to emit */
   
   /* Do this here as we may have flushed the batchbuffer above,
    * causing more state to be dirty!
    */
   dirty = get_dirty(state);
   state->emitted |= dirty;
   assert(get_dirty(state) == 0);

   if (INTEL_DEBUG & DEBUG_STATE)
      fprintf(stderr, "%s dirty: %x\n", __func__, dirty);

   if (dirty & I915_UPLOAD_INVARIENT) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_INVARIENT:\n");
      i915_emit_invarient_state(intel);
   }

   if (dirty & I915_UPLOAD_RASTER_RULES) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_RASTER_RULES:\n");
      emit(intel, state->RasterRules, sizeof(state->RasterRules));
   }

   if (dirty & I915_UPLOAD_CTX) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_CTX:\n");

      emit(intel, state->Ctx, sizeof(state->Ctx));
   }

   if (dirty & I915_UPLOAD_BLEND) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_BLEND:\n");

      emit(intel, state->Blend, sizeof(state->Blend));
   }

   if (dirty & I915_UPLOAD_BUFFERS) {
      GLuint count;

      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_BUFFERS:\n");

      count = 17;
      if (state->Buffer[I915_DESTREG_DRAWRECT0] != MI_NOOP)
         count++;

      BEGIN_BATCH(count);
      OUT_BATCH(state->Buffer[I915_DESTREG_CBUFADDR0]);
      OUT_BATCH(state->Buffer[I915_DESTREG_CBUFADDR1]);
      if (state->draw_region) {
	 OUT_RELOC(state->draw_region->bo,
		   I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER, 0);
      } else {
	 OUT_BATCH(0);
      }

      OUT_BATCH(state->Buffer[I915_DESTREG_DBUFADDR0]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DBUFADDR1]);
      if (state->depth_region) {
         OUT_RELOC(state->depth_region->bo,
		   I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER, 0);
      } else {
	 OUT_BATCH(0);
      }

      OUT_BATCH(state->Buffer[I915_DESTREG_DV0]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DV1]);
      OUT_BATCH(state->Buffer[I915_DESTREG_SR0]);
      OUT_BATCH(state->Buffer[I915_DESTREG_SR1]);
      OUT_BATCH(state->Buffer[I915_DESTREG_SR2]);
      OUT_BATCH(state->Buffer[I915_DESTREG_SENABLE]);

      if (state->Buffer[I915_DESTREG_DRAWRECT0] != MI_NOOP)
         OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT0]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT1]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT2]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT3]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT4]);
      OUT_BATCH(state->Buffer[I915_DESTREG_DRAWRECT5]);

      ADVANCE_BATCH();
   }

   if (dirty & I915_UPLOAD_STIPPLE) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_STIPPLE:\n");
      emit(intel, state->Stipple, sizeof(state->Stipple));
   }

   /* Combine all the dirty texture state into a single command to
    * avoid lockups on I915 hardware. 
    */
   if (dirty & I915_UPLOAD_TEX_ALL) {
      int nr = 0;
      GLuint unwind;

      for (i = 0; i < I915_TEX_UNITS; i++)
         if (dirty & I915_UPLOAD_TEX(i))
            nr++;

      BEGIN_BATCH(2 + nr * 3);
      OUT_BATCH(_3DSTATE_MAP_STATE | (3 * nr));
      OUT_BATCH((dirty & I915_UPLOAD_TEX_ALL) >> I915_UPLOAD_TEX_0_SHIFT);
      for (i = 0; i < I915_TEX_UNITS; i++)
         if (dirty & I915_UPLOAD_TEX(i)) {
	    OUT_RELOC(state->tex_buffer[i],
		      I915_GEM_DOMAIN_SAMPLER, 0,
		      state->tex_offset[i]);

            OUT_BATCH(state->Tex[i][I915_TEXREG_MS3]);
            OUT_BATCH(state->Tex[i][I915_TEXREG_MS4]);
         }
      ADVANCE_BATCH();

      unwind = intel->batch.used;
      BEGIN_BATCH(2 + nr * 3);
      OUT_BATCH(_3DSTATE_SAMPLER_STATE | (3 * nr));
      OUT_BATCH((dirty & I915_UPLOAD_TEX_ALL) >> I915_UPLOAD_TEX_0_SHIFT);
      for (i = 0; i < I915_TEX_UNITS; i++)
         if (dirty & I915_UPLOAD_TEX(i)) {
            OUT_BATCH(state->Tex[i][I915_TEXREG_SS2]);
            OUT_BATCH(state->Tex[i][I915_TEXREG_SS3]);
            OUT_BATCH(state->Tex[i][I915_TEXREG_SS4]);
         }
      ADVANCE_BATCH();
      if (i915->last_sampler &&
	  memcmp(intel->batch.map + i915->last_sampler,
		 intel->batch.map + unwind,
		 (2 + nr*3)*sizeof(int)) == 0)
	  intel->batch.used = unwind;
      else
	  i915->last_sampler = unwind;
   }

   if (dirty & I915_UPLOAD_CONSTANTS) {
      if (INTEL_DEBUG & DEBUG_STATE)
         fprintf(stderr, "I915_UPLOAD_CONSTANTS:\n");
      emit(intel, state->Constant, state->ConstantSize * sizeof(GLuint));
   }

   if (dirty & I915_UPLOAD_PROGRAM) {
      if (state->ProgramSize) {
         if (INTEL_DEBUG & DEBUG_STATE)
            fprintf(stderr, "I915_UPLOAD_PROGRAM:\n");

         assert((state->Program[0] & 0x1ff) + 2 == state->ProgramSize);

         emit(intel, state->Program, state->ProgramSize * sizeof(GLuint));
         if (INTEL_DEBUG & DEBUG_STATE)
            i915_disassemble_program(state->Program, state->ProgramSize);
      }
   }

   assert(get_dirty(state) == 0);
}

static void
i915_destroy_context(struct intel_context *intel)
{
   GLuint i;
   struct i915_context *i915 = i915_context(&intel->ctx);

   intel_region_release(&i915->state.draw_region);
   intel_region_release(&i915->state.depth_region);

   for (i = 0; i < I915_TEX_UNITS; i++) {
      if (i915->state.tex_buffer[i] != NULL) {
	 drm_intel_bo_unreference(i915->state.tex_buffer[i]);
	 i915->state.tex_buffer[i] = NULL;
      }
   }

   _tnl_free_vertices(&intel->ctx);
}

void
i915_set_buf_info_for_region(uint32_t *state, struct intel_region *region,
			     uint32_t buffer_id)
{
   state[0] = _3DSTATE_BUF_INFO_CMD;
   state[1] = buffer_id;

   if (region != NULL) {
      state[1] |= BUF_3D_PITCH(region->pitch);

      if (region->tiling != I915_TILING_NONE) {
	 state[1] |= BUF_3D_TILED_SURFACE;
	 if (region->tiling == I915_TILING_Y)
	    state[1] |= BUF_3D_TILE_WALK_Y;
      }
   } else {
      /* Fill in a default pitch, since 0 is invalid.  We'll be
       * setting the buffer offset to 0 and not referencing the
       * buffer, so the pitch could really be any valid value.
       */
      state[1] |= BUF_3D_PITCH(4096);
   }
}

static uint32_t i915_render_target_format_for_mesa_format[MESA_FORMAT_COUNT] =
{
   [MESA_FORMAT_B8G8R8A8_UNORM] = DV_PF_8888,
   [MESA_FORMAT_B8G8R8X8_UNORM] = DV_PF_8888,
   [MESA_FORMAT_R8G8B8X8_UNORM] = DV_PF_8888,
   [MESA_FORMAT_B5G6R5_UNORM] = DV_PF_565 | DITHER_FULL_ALWAYS,
   [MESA_FORMAT_B5G5R5A1_UNORM] = DV_PF_1555 | DITHER_FULL_ALWAYS,
   [MESA_FORMAT_B4G4R4A4_UNORM] = DV_PF_4444 | DITHER_FULL_ALWAYS,
};

static bool
i915_render_target_supported(struct intel_context *intel,
			     struct gl_renderbuffer *rb)
{
   mesa_format format = rb->Format;

   if (format == MESA_FORMAT_Z24_UNORM_S8_UINT ||
       format == MESA_FORMAT_Z24_UNORM_X8_UINT ||
       format == MESA_FORMAT_Z_UNORM16) {
      return true;
   }

   return i915_render_target_format_for_mesa_format[format] != 0;
}

static void
i915_set_draw_region(struct intel_context *intel,
                     struct intel_region *color_regions[],
                     struct intel_region *depth_region,
		     GLuint num_regions)
{
   struct i915_context *i915 = i915_context(&intel->ctx);
   struct gl_context *ctx = &intel->ctx;
   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0];
   struct intel_renderbuffer *irb = intel_renderbuffer(rb);
   struct gl_renderbuffer *drb;
   struct intel_renderbuffer *idrb = NULL;
   GLuint value;
   struct i915_hw_state *state = &i915->state;
   uint32_t draw_x, draw_y, draw_offset;

   if (state->draw_region != color_regions[0]) {
      intel_region_reference(&state->draw_region, color_regions[0]);
   }
   if (state->depth_region != depth_region) {
      intel_region_reference(&state->depth_region, depth_region);
   }

   /*
    * Set stride/cpp values
    */
   i915_set_buf_info_for_region(&state->Buffer[I915_DESTREG_CBUFADDR0],
				color_regions[0], BUF_3D_ID_COLOR_BACK);

   i915_set_buf_info_for_region(&state->Buffer[I915_DESTREG_DBUFADDR0],
				depth_region, BUF_3D_ID_DEPTH);

   /*
    * Compute/set I915_DESTREG_DV1 value
    */
   value = (DSTORG_HORT_BIAS(0x8) |     /* .5 */
            DSTORG_VERT_BIAS(0x8) |     /* .5 */
            LOD_PRECLAMP_OGL | TEX_DEFAULT_COLOR_OGL);
   if (irb != NULL) {
      value |= i915_render_target_format_for_mesa_format[intel_rb_format(irb)];
   } else {
      value |= DV_PF_8888;
   }

   /* This isn't quite safe, thus being hidden behind an option.  When changing
    * the value of this bit, the pipeline needs to be MI_FLUSHed.  And it
    * can only be set when a depth buffer is already defined.
    */
   if (intel->is_945 && intel->use_early_z &&
       depth_region->tiling != I915_TILING_NONE)
      value |= CLASSIC_EARLY_DEPTH;

   if (depth_region && depth_region->cpp == 4) {
      value |= DEPTH_FRMT_24_FIXED_8_OTHER;
   }
   else {
      value |= DEPTH_FRMT_16_FIXED;
   }
   state->Buffer[I915_DESTREG_DV1] = value;

   drb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
   if (!drb)
      drb = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;

   if (drb)
      idrb = intel_renderbuffer(drb);

   /* We set up the drawing rectangle to be offset into the color
    * region's location in the miptree.  If it doesn't match with
    * depth's offsets, we can't render to it.
    *
    * (Well, not actually true -- the hw grew a bit to let depth's
    * offset get forced to 0,0.  We may want to use that if people are
    * hitting that case.  Also, some configurations may be supportable
    * by tweaking the start offset of the buffers around, which we
    * can't do in general due to tiling)
    */
   FALLBACK(intel, I915_FALLBACK_DRAW_OFFSET,
	    idrb && irb && (idrb->draw_x != irb->draw_x ||
			    idrb->draw_y != irb->draw_y));

   if (irb) {
      draw_x = irb->draw_x;
      draw_y = irb->draw_y;
   } else if (idrb) {
      draw_x = idrb->draw_x;
      draw_y = idrb->draw_y;
   } else {
      draw_x = 0;
      draw_y = 0;
   }

   draw_offset = (draw_y << 16) | draw_x;

   FALLBACK(intel, I915_FALLBACK_DRAW_OFFSET,
            (ctx->DrawBuffer->Width + draw_x > 2048) ||
            (ctx->DrawBuffer->Height + draw_y > 2048));
   /* When changing drawing rectangle offset, an MI_FLUSH is first required. */
   if (draw_offset != i915->last_draw_offset) {
      state->Buffer[I915_DESTREG_DRAWRECT0] = MI_FLUSH | INHIBIT_FLUSH_RENDER_CACHE;
      i915->last_draw_offset = draw_offset;
   } else
      state->Buffer[I915_DESTREG_DRAWRECT0] = MI_NOOP;

   state->Buffer[I915_DESTREG_DRAWRECT1] = _3DSTATE_DRAWRECT_INFO;
   state->Buffer[I915_DESTREG_DRAWRECT2] = 0;
   state->Buffer[I915_DESTREG_DRAWRECT3] = draw_offset;
   state->Buffer[I915_DESTREG_DRAWRECT4] =
      ((ctx->DrawBuffer->Width + draw_x - 1) & 0xffff) |
      ((ctx->DrawBuffer->Height + draw_y - 1) << 16);
   state->Buffer[I915_DESTREG_DRAWRECT5] = draw_offset;

   I915_STATECHANGE(i915, I915_UPLOAD_BUFFERS);
}

static void
i915_update_color_write_enable(struct i915_context *i915, bool enable)
{
   uint32_t dw = i915->state.Ctx[I915_CTXREG_LIS6];
   if (enable)
      dw |= S6_COLOR_WRITE_ENABLE;
   else
      dw &= ~S6_COLOR_WRITE_ENABLE;
   if (dw != i915->state.Ctx[I915_CTXREG_LIS6]) {
      I915_STATECHANGE(i915, I915_UPLOAD_CTX);
      i915->state.Ctx[I915_CTXREG_LIS6] = dw;
   }
}

/**
 * Update the hardware state for drawing into a window or framebuffer object.
 *
 * Called by glDrawBuffer, glBindFramebufferEXT, MakeCurrent, and other
 * places within the driver.
 *
 * Basically, this needs to be called any time the current framebuffer
 * changes, the renderbuffers change, or we need to draw into different
 * color buffers.
 */
static void
i915_update_draw_buffer(struct intel_context *intel)
{
   struct i915_context *i915 = (struct i915_context *)intel;
   struct gl_context *ctx = &intel->ctx;
   struct gl_framebuffer *fb = ctx->DrawBuffer;
   struct intel_region *colorRegion = NULL, *depthRegion = NULL;
   struct intel_renderbuffer *irbDepth = NULL, *irbStencil = NULL;

   if (!fb) {
      /* this can happen during the initial context initialization */
      return;
   }

   irbDepth = intel_get_renderbuffer(fb, BUFFER_DEPTH);
   irbStencil = intel_get_renderbuffer(fb, BUFFER_STENCIL);

   /* Do this here, not core Mesa, since this function is called from
    * many places within the driver.
    */
   if (ctx->NewState & _NEW_BUFFERS) {
      /* this updates the DrawBuffer->_NumColorDrawBuffers fields, etc */
      _mesa_update_framebuffer(ctx, ctx->ReadBuffer, ctx->DrawBuffer);
      /* this updates the DrawBuffer's Width/Height if it's a FBO */
      _mesa_update_draw_buffer_bounds(ctx, ctx->DrawBuffer);
   }

   if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      /* this may occur when we're called by glBindFrameBuffer() during
       * the process of someone setting up renderbuffers, etc.
       */
      /*_mesa_debug(ctx, "DrawBuffer: incomplete user FBO\n");*/
      return;
   }

   /* How many color buffers are we drawing into?
    *
    * If there is more than one drawbuffer (GL_FRONT_AND_BACK), or the
    * drawbuffers are too big, we have to fallback to software.
    */
   if ((fb->Width > ctx->Const.MaxRenderbufferSize)
       || (fb->Height > ctx->Const.MaxRenderbufferSize)) {
      FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, true);
   } else if (fb->_NumColorDrawBuffers > 1) {
      FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, true);
   } else {
      struct intel_renderbuffer *irb;
      irb = intel_renderbuffer(fb->_ColorDrawBuffers[0]);
      colorRegion = (irb && irb->mt) ? irb->mt->region : NULL;
      FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, false);
   }

   /* Check for depth fallback. */
   if (irbDepth && irbDepth->mt) {
      FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, false);
      depthRegion = irbDepth->mt->region;
   } else if (irbDepth && !irbDepth->mt) {
      FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, true);
      depthRegion = NULL;
   } else { /* !irbDepth */
      /* No fallback is needed because there is no depth buffer. */
      FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, false);
      depthRegion = NULL;
   }

   /* Check for stencil fallback. */
   if (irbStencil && irbStencil->mt) {
      assert(intel_rb_format(irbStencil) == MESA_FORMAT_Z24_UNORM_S8_UINT);
      FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, false);
   } else if (irbStencil && !irbStencil->mt) {
      FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, true);
   } else { /* !irbStencil */
      /* No fallback is needed because there is no stencil buffer. */
      FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, false);
   }

   /* If we have a (packed) stencil buffer attached but no depth buffer,
    * we still need to set up the shared depth/stencil state so we can use it.
    */
   if (depthRegion == NULL && irbStencil && irbStencil->mt
       && intel_rb_format(irbStencil) == MESA_FORMAT_Z24_UNORM_S8_UINT) {
      depthRegion = irbStencil->mt->region;
   }

   /*
    * Update depth and stencil test state
    */
   ctx->Driver.Enable(ctx, GL_DEPTH_TEST, ctx->Depth.Test);
   ctx->Driver.Enable(ctx, GL_STENCIL_TEST, ctx->Stencil.Enabled);

   i915_update_color_write_enable(i915, colorRegion != NULL);

   intel->vtbl.set_draw_region(intel, &colorRegion, depthRegion,
                               fb->_NumColorDrawBuffers);
   intel->NewGLState |= _NEW_BUFFERS;

   /* Set state we know depends on drawable parameters:
    */
   intelCalcViewport(ctx);
   ctx->Driver.Scissor(ctx);

   /* Update culling direction which changes depending on the
    * orientation of the buffer:
    */
   ctx->Driver.FrontFace(ctx, ctx->Polygon.FrontFace);
}

static void
i915_new_batch(struct intel_context *intel)
{
   struct i915_context *i915 = i915_context(&intel->ctx);

   /* Mark all state as needing to be emitted when starting a new batchbuffer.
    * Using hardware contexts would be an alternative, but they have some
    * difficulties associated with them (physical address requirements).
    */
   i915->state.emitted = 0;
   i915->last_draw_offset = 0;
   i915->last_sampler = 0;

   i915->current_vb_bo = NULL;
   i915->current_vertex_size = 0;
}

static void 
i915_assert_not_dirty( struct intel_context *intel )
{
   struct i915_context *i915 = i915_context(&intel->ctx);
   GLuint dirty = get_dirty(&i915->state);
   assert(!dirty);
   (void) dirty;
}

static void
i915_invalidate_state(struct intel_context *intel, GLuint new_state)
{
   struct gl_context *ctx = &intel->ctx;

   _swsetup_InvalidateState(ctx, new_state);
   _tnl_InvalidateState(ctx, new_state);
   _tnl_invalidate_vertex_state(ctx, new_state);
}

void
i915InitVtbl(struct i915_context *i915)
{
   i915->intel.vtbl.check_vertex_size = i915_check_vertex_size;
   i915->intel.vtbl.destroy = i915_destroy_context;
   i915->intel.vtbl.emit_state = i915_emit_state;
   i915->intel.vtbl.new_batch = i915_new_batch;
   i915->intel.vtbl.reduced_primitive_state = i915_reduced_primitive_state;
   i915->intel.vtbl.render_start = i915_render_start;
   i915->intel.vtbl.render_prevalidate = i915_render_prevalidate;
   i915->intel.vtbl.set_draw_region = i915_set_draw_region;
   i915->intel.vtbl.update_draw_buffer = i915_update_draw_buffer;
   i915->intel.vtbl.update_texture_state = i915UpdateTextureState;
   i915->intel.vtbl.assert_not_dirty = i915_assert_not_dirty;
   i915->intel.vtbl.finish_batch = intel_finish_vb;
   i915->intel.vtbl.invalidate_state = i915_invalidate_state;
   i915->intel.vtbl.render_target_supported = i915_render_target_supported;
}
