drm/radeon/kms: add a CS ioctl flag not to rewrite tiling flags in the CS

This adds a new optional chunk to the CS ioctl that specifies optional flags
to the CS parser. Why this is useful is explained below. Note that some regs
no longer need the NOP relocation packet if this feature is enabled.
Tested on r300g and r600g with this flag disabled and enabled.

Assume there are two contexts sharing the same mipmapped tiled texture.
One context wants to render into the first mipmap and the other one
wants to render into the last mipmap. As you probably know, the hardware
has a MACRO_SWITCH feature, which turns off macro tiling for small mipmaps,
but that only applies to samplers.
(at least on r300-r500, though later hardware likely behaves the same)

So we want to just re-set the tiling flags before rendering (writing
packets), right? ... No. The contexts run in parallel, so they may
set the tiling flags simultaneously and then fire their command streams
also simultaneously. The last one setting the flags wins, the other one
loses.

Another problem is when one context wants to render into the first and
the last mipmap in one CS. Impossible. It must flush before changing
tiling flags and do the rendering into the smaller mipmaps in another CS.

Yet another problem is that writing copy_blit in userspace would be a mess
involving re-setting tiling flags to please the kernel, and causing races
with other contexts at the same time.

The only way out of this is to send tiling flags with each CS, ideally
with each relocation. But we already do that through the registers.
So let's just use what we have in the registers.

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/radeon/evergreen_cs.c b/drivers/gpu/drm/radeon/evergreen_cs.c
index 7fdfa8e..38e1bda 100644 (file)
--- a/drivers/gpu/drm/radeon/evergreen_cs.c
+++ b/drivers/gpu/drm/radeon/evergreen_cs.c
@@ -480,21 +480,23 @@ static int evergreen_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
                }
                break;
        case DB_Z_INFO:
-               r = evergreen_cs_packet_next_reloc(p, &reloc);
-               if (r) {
-                       dev_warn(p->dev, "bad SET_CONTEXT_REG "
-                                       "0x%04X\n", reg);
-                       return -EINVAL;
-               }
                track->db_z_info = radeon_get_ib_value(p, idx);
-               ib[idx] &= ~Z_ARRAY_MODE(0xf);
-               track->db_z_info &= ~Z_ARRAY_MODE(0xf);
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
-                       ib[idx] |= Z_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-                       track->db_z_info |= Z_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-               } else {
-                       ib[idx] |= Z_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
-                       track->db_z_info |= Z_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+               if (!p->keep_tiling_flags) {
+                       r = evergreen_cs_packet_next_reloc(p, &reloc);
+                       if (r) {
+                               dev_warn(p->dev, "bad SET_CONTEXT_REG "
+                                               "0x%04X\n", reg);
+                               return -EINVAL;
+                       }
+                       ib[idx] &= ~Z_ARRAY_MODE(0xf);
+                       track->db_z_info &= ~Z_ARRAY_MODE(0xf);
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
+                               ib[idx] |= Z_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                               track->db_z_info |= Z_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                       } else {
+                               ib[idx] |= Z_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                               track->db_z_info |= Z_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                       }
                }
                break;
        case DB_STENCIL_INFO:
@@ -607,40 +609,44 @@ static int evergreen_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
        case CB_COLOR5_INFO:
        case CB_COLOR6_INFO:
        case CB_COLOR7_INFO:
-               r = evergreen_cs_packet_next_reloc(p, &reloc);
-               if (r) {
-                       dev_warn(p->dev, "bad SET_CONTEXT_REG "
-                                       "0x%04X\n", reg);
-                       return -EINVAL;
-               }
                tmp = (reg - CB_COLOR0_INFO) / 0x3c;
                track->cb_color_info[tmp] = radeon_get_ib_value(p, idx);
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
-                       ib[idx] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-                       track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-               } else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO) {
-                       ib[idx] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
-                       track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+               if (!p->keep_tiling_flags) {
+                       r = evergreen_cs_packet_next_reloc(p, &reloc);
+                       if (r) {
+                               dev_warn(p->dev, "bad SET_CONTEXT_REG "
+                                               "0x%04X\n", reg);
+                               return -EINVAL;
+                       }
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
+                               ib[idx] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                               track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                       } else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO) {
+                               ib[idx] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                               track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                       }
                }
                break;
        case CB_COLOR8_INFO:
        case CB_COLOR9_INFO:
        case CB_COLOR10_INFO:
        case CB_COLOR11_INFO:
-               r = evergreen_cs_packet_next_reloc(p, &reloc);
-               if (r) {
-                       dev_warn(p->dev, "bad SET_CONTEXT_REG "
-                                       "0x%04X\n", reg);
-                       return -EINVAL;
-               }
                tmp = ((reg - CB_COLOR8_INFO) / 0x1c) + 8;
                track->cb_color_info[tmp] = radeon_get_ib_value(p, idx);
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
-                       ib[idx] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-                       track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-               } else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO) {
-                       ib[idx] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
-                       track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+               if (!p->keep_tiling_flags) {
+                       r = evergreen_cs_packet_next_reloc(p, &reloc);
+                       if (r) {
+                               dev_warn(p->dev, "bad SET_CONTEXT_REG "
+                                               "0x%04X\n", reg);
+                               return -EINVAL;
+                       }
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO) {
+                               ib[idx] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                               track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                       } else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO) {
+                               ib[idx] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                               track->cb_color_info[tmp] |= CB_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                       }
                }
                break;
        case CB_COLOR0_PITCH:
@@ -1311,10 +1317,12 @@ static int evergreen_packet3_check(struct radeon_cs_parser *p,
                                        return -EINVAL;
                                }
                                ib[idx+1+(i*8)+2] += (u32)((reloc->lobj.gpu_offset >> 8) & 0xffffffff);
-                               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
-                                       ib[idx+1+(i*8)+1] |= TEX_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
-                               else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
-                                       ib[idx+1+(i*8)+1] |= TEX_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                               if (!p->keep_tiling_flags) {
+                                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
+                                               ib[idx+1+(i*8)+1] |= TEX_ARRAY_MODE(ARRAY_2D_TILED_THIN1);
+                                       else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
+                                               ib[idx+1+(i*8)+1] |= TEX_ARRAY_MODE(ARRAY_1D_TILED_THIN1);
+                               }
                                texture = reloc->robj;
                                /* tex mip base */
                                r = evergreen_cs_packet_next_reloc(p, &reloc);

diff --git a/drivers/gpu/drm/radeon/r300.c b/drivers/gpu/drm/radeon/r300.c
index 400b26d..c93bc64 100644 (file)
--- a/drivers/gpu/drm/radeon/r300.c
+++ b/drivers/gpu/drm/radeon/r300.c
@@ -701,16 +701,21 @@ static int r300_packet0_check(struct radeon_cs_parser *p,
                        return r;
                }
 
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
-                       tile_flags |= R300_TXO_MACRO_TILE;
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
-                       tile_flags |= R300_TXO_MICRO_TILE;
-               else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
-                       tile_flags |= R300_TXO_MICRO_TILE_SQUARE;
-
-               tmp = idx_value + ((u32)reloc->lobj.gpu_offset);
-               tmp |= tile_flags;
-               ib[idx] = tmp;
+               if (p->keep_tiling_flags) {
+                       ib[idx] = (idx_value & 31) | /* keep the 1st 5 bits */
+                                 ((idx_value & ~31) + (u32)reloc->lobj.gpu_offset);
+               } else {
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
+                               tile_flags |= R300_TXO_MACRO_TILE;
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
+                               tile_flags |= R300_TXO_MICRO_TILE;
+                       else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
+                               tile_flags |= R300_TXO_MICRO_TILE_SQUARE;
+
+                       tmp = idx_value + ((u32)reloc->lobj.gpu_offset);
+                       tmp |= tile_flags;
+                       ib[idx] = tmp;
+               }
                track->textures[i].robj = reloc->robj;
                track->tex_dirty = true;
                break;
@@ -760,24 +765,26 @@ static int r300_packet0_check(struct radeon_cs_parser *p,
                /* RB3D_COLORPITCH1 */
                /* RB3D_COLORPITCH2 */
                /* RB3D_COLORPITCH3 */
-               r = r100_cs_packet_next_reloc(p, &reloc);
-               if (r) {
-                       DRM_ERROR("No reloc for ib[%d]=0x%04X\n",
-                                 idx, reg);
-                       r100_cs_dump_packet(p, pkt);
-                       return r;
-               }
+               if (!p->keep_tiling_flags) {
+                       r = r100_cs_packet_next_reloc(p, &reloc);
+                       if (r) {
+                               DRM_ERROR("No reloc for ib[%d]=0x%04X\n",
+                                         idx, reg);
+                               r100_cs_dump_packet(p, pkt);
+                               return r;
+                       }
 
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
-                       tile_flags |= R300_COLOR_TILE_ENABLE;
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
-                       tile_flags |= R300_COLOR_MICROTILE_ENABLE;
-               else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
-                       tile_flags |= R300_COLOR_MICROTILE_SQUARE_ENABLE;
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
+                               tile_flags |= R300_COLOR_TILE_ENABLE;
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
+                               tile_flags |= R300_COLOR_MICROTILE_ENABLE;
+                       else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
+                               tile_flags |= R300_COLOR_MICROTILE_SQUARE_ENABLE;
 
-               tmp = idx_value & ~(0x7 << 16);
-               tmp |= tile_flags;
-               ib[idx] = tmp;
+                       tmp = idx_value & ~(0x7 << 16);
+                       tmp |= tile_flags;
+                       ib[idx] = tmp;
+               }
                i = (reg - 0x4E38) >> 2;
                track->cb[i].pitch = idx_value & 0x3FFE;
                switch (((idx_value >> 21) & 0xF)) {
@@ -843,25 +850,26 @@ static int r300_packet0_check(struct radeon_cs_parser *p,
                break;
        case 0x4F24:
                /* ZB_DEPTHPITCH */
-               r = r100_cs_packet_next_reloc(p, &reloc);
-               if (r) {
-                       DRM_ERROR("No reloc for ib[%d]=0x%04X\n",
-                                 idx, reg);
-                       r100_cs_dump_packet(p, pkt);
-                       return r;
-               }
-
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
-                       tile_flags |= R300_DEPTHMACROTILE_ENABLE;
-               if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
-                       tile_flags |= R300_DEPTHMICROTILE_TILED;
-               else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
-                       tile_flags |= R300_DEPTHMICROTILE_TILED_SQUARE;
+               if (!p->keep_tiling_flags) {
+                       r = r100_cs_packet_next_reloc(p, &reloc);
+                       if (r) {
+                               DRM_ERROR("No reloc for ib[%d]=0x%04X\n",
+                                         idx, reg);
+                               r100_cs_dump_packet(p, pkt);
+                               return r;
+                       }
 
-               tmp = idx_value & ~(0x7 << 16);
-               tmp |= tile_flags;
-               ib[idx] = tmp;
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
+                               tile_flags |= R300_DEPTHMACROTILE_ENABLE;
+                       if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
+                               tile_flags |= R300_DEPTHMICROTILE_TILED;
+                       else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO_SQUARE)
+                               tile_flags |= R300_DEPTHMICROTILE_TILED_SQUARE;
 
+                       tmp = idx_value & ~(0x7 << 16);
+                       tmp |= tile_flags;
+                       ib[idx] = tmp;
+               }
                track->zb.pitch = idx_value & 0x3FFC;
                track->zb_dirty = true;
                break;

diff --git a/drivers/gpu/drm/radeon/r600_cs.c b/drivers/gpu/drm/radeon/r600_cs.c
index 0a2e023..cb1acff 100644 (file)
--- a/drivers/gpu/drm/radeon/r600_cs.c
+++ b/drivers/gpu/drm/radeon/r600_cs.c
@@ -941,7 +941,8 @@ static int r600_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
                track->db_depth_control = radeon_get_ib_value(p, idx);
                break;
        case R_028010_DB_DEPTH_INFO:
-               if (r600_cs_packet_next_is_pkt3_nop(p)) {
+               if (!p->keep_tiling_flags &&
+                   r600_cs_packet_next_is_pkt3_nop(p)) {
                        r = r600_cs_packet_next_reloc(p, &reloc);
                        if (r) {
                                dev_warn(p->dev, "bad SET_CONTEXT_REG "
@@ -992,7 +993,8 @@ static int r600_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
        case R_0280B4_CB_COLOR5_INFO:
        case R_0280B8_CB_COLOR6_INFO:
        case R_0280BC_CB_COLOR7_INFO:
-               if (r600_cs_packet_next_is_pkt3_nop(p)) {
+               if (!p->keep_tiling_flags &&
+                    r600_cs_packet_next_is_pkt3_nop(p)) {
                        r = r600_cs_packet_next_reloc(p, &reloc);
                        if (r) {
                                dev_err(p->dev, "bad SET_CONTEXT_REG 0x%04X\n", reg);
@@ -1291,10 +1293,12 @@ static int r600_check_texture_resource(struct radeon_cs_parser *p,  u32 idx,
        mip_offset <<= 8;
 
        word0 = radeon_get_ib_value(p, idx + 0);
-       if (tiling_flags & RADEON_TILING_MACRO)
-               word0 |= S_038000_TILE_MODE(V_038000_ARRAY_2D_TILED_THIN1);
-       else if (tiling_flags & RADEON_TILING_MICRO)
-               word0 |= S_038000_TILE_MODE(V_038000_ARRAY_1D_TILED_THIN1);
+       if (!p->keep_tiling_flags) {
+               if (tiling_flags & RADEON_TILING_MACRO)
+                       word0 |= S_038000_TILE_MODE(V_038000_ARRAY_2D_TILED_THIN1);
+               else if (tiling_flags & RADEON_TILING_MICRO)
+                       word0 |= S_038000_TILE_MODE(V_038000_ARRAY_1D_TILED_THIN1);
+       }
        word1 = radeon_get_ib_value(p, idx + 1);
        w0 = G_038000_TEX_WIDTH(word0) + 1;
        h0 = G_038004_TEX_HEIGHT(word1) + 1;
@@ -1621,10 +1625,12 @@ static int r600_packet3_check(struct radeon_cs_parser *p,
                                        return -EINVAL;
                                }
                                base_offset = (u32)((reloc->lobj.gpu_offset >> 8) & 0xffffffff);
-                               if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
-                                       ib[idx+1+(i*7)+0] |= S_038000_TILE_MODE(V_038000_ARRAY_2D_TILED_THIN1);
-                               else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
-                                       ib[idx+1+(i*7)+0] |= S_038000_TILE_MODE(V_038000_ARRAY_1D_TILED_THIN1);
+                               if (!p->keep_tiling_flags) {
+                                       if (reloc->lobj.tiling_flags & RADEON_TILING_MACRO)
+                                               ib[idx+1+(i*7)+0] |= S_038000_TILE_MODE(V_038000_ARRAY_2D_TILED_THIN1);
+                                       else if (reloc->lobj.tiling_flags & RADEON_TILING_MICRO)
+                                               ib[idx+1+(i*7)+0] |= S_038000_TILE_MODE(V_038000_ARRAY_1D_TILED_THIN1);
+                               }
                                texture = reloc->robj;
                                /* tex mip base */
                                r = r600_cs_packet_next_reloc(p, &reloc);

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index fc5a1d6..8227e76 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -611,7 +611,8 @@ struct radeon_cs_parser {
        struct radeon_ib        *ib;
        void                    *track;
        unsigned                family;
-       int parser_error;
+       int                     parser_error;
+       bool                    keep_tiling_flags;
 };
 
 extern int radeon_cs_update_pages(struct radeon_cs_parser *p, int pg_idx);

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index ccaa243..29afd71 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -93,7 +93,7 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
 {
        struct drm_radeon_cs *cs = data;
        uint64_t *chunk_array_ptr;
-       unsigned size, i;
+       unsigned size, i, flags = 0;
 
        if (!cs->num_chunks) {
                return 0;
@@ -140,6 +140,10 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
                        if (p->chunks[i].length_dw == 0)
                                return -EINVAL;
                }
+               if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_FLAGS &&
+                   !p->chunks[i].length_dw) {
+                       return -EINVAL;
+               }
 
                p->chunks[i].length_dw = user_chunk.length_dw;
                p->chunks[i].user_ptr = (void __user *)(unsigned long)user_chunk.chunk_data;
@@ -155,6 +159,9 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
                                               p->chunks[i].user_ptr, size)) {
                                return -EFAULT;
                        }
+                       if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_FLAGS) {
+                               flags = p->chunks[i].kdata[0];
+                       }
                } else {
                        p->chunks[i].kpage[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
                        p->chunks[i].kpage[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
@@ -174,6 +181,8 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
                          p->chunks[p->chunk_ib_idx].length_dw);
                return -EINVAL;
        }
+
+       p->keep_tiling_flags = (flags & RADEON_CS_KEEP_TILING_FLAGS) != 0;
        return 0;
 }
 

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index a0b35e9..71499fc 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -53,9 +53,10 @@
  *   2.9.0 - r600 tiling (s3tc,rgtc) working, SET_PREDICATION packet 3 on r600 + eg, backend query
  *   2.10.0 - fusion 2D tiling
  *   2.11.0 - backend map, initial compute support for the CS checker
+ *   2.12.0 - RADEON_CS_KEEP_TILING_FLAGS
  */
 #define KMS_DRIVER_MAJOR       2
-#define KMS_DRIVER_MINOR       11
+#define KMS_DRIVER_MINOR       12
 #define KMS_DRIVER_PATCHLEVEL  0
 int radeon_driver_load_kms(struct drm_device *dev, unsigned long flags);
 int radeon_driver_unload_kms(struct drm_device *dev);

diff --git a/include/drm/radeon_drm.h b/include/drm/radeon_drm.h
index b65be60..be94be6 100644 (file)
--- a/include/drm/radeon_drm.h
+++ b/include/drm/radeon_drm.h
@@ -874,6 +874,10 @@ struct drm_radeon_gem_pwrite {
 
 #define RADEON_CHUNK_ID_RELOCS 0x01
 #define RADEON_CHUNK_ID_IB     0x02
+#define RADEON_CHUNK_ID_FLAGS  0x03
+
+/* The first dword of RADEON_CHUNK_ID_FLAGS is a uint32 of these flags: */
+#define RADEON_CS_KEEP_TILING_FLAGS 0x01
 
 struct drm_radeon_cs_chunk {
        uint32_t                chunk_id;