Avoid GPU crash with malformed streams

When streams are malformed, we can get p-frames without any reference
picture. However the code still assumes 1 reference picture at least,
which leads to a GPU crash. To protect against GPU crashes, we force 0
when we have no pictures. Do this on gen6, 7, 7.5 and 8.

BUG=chromium:252389,chroimum:418024
TEST=go to youtube and play http://www.youtube.com/watch?v=6v2L2UGZJAM ; it doesn't crash

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Sean V Kelley <seanvk@posteo.de>

Author: marcheu

src/gen6_mfd.c

@@ -515,6 +515,8 @@ gen6_mfd_avc_slice_state(VADriverContextP ctx,
     int first_mb_in_slice = 0, first_mb_in_next_slice = 0;
     unsigned int chroma_log2_weight_denom, luma_log2_weight_denom;
     int slice_type;
+    int num_surfaces = 0;
+    int i;
 
     if (slice_param->slice_type == SLICE_TYPE_I ||
         slice_param->slice_type == SLICE_TYPE_SI) {
@@ -552,6 +554,15 @@ gen6_mfd_avc_slice_state(VADriverContextP ctx,
         }
     }
 
+    /* Don't bind a surface which doesn't exist, that crashes the GPU */
+    for (i = 0; i < ARRAY_ELEMS(gen6_mfd_context->reference_surface); i++)
+        if (gen6_mfd_context->reference_surface[i].surface_id != VA_INVALID_ID)
+            num_surfaces ++;
+    if (num_surfaces == 0) {
+        num_ref_idx_l0 = 0;
+        num_ref_idx_l1 = 0;
+    }
+
     first_mb_in_slice = slice_param->first_mb_in_slice;
     slice_hor_pos = first_mb_in_slice % width_in_mbs;
     slice_ver_pos = first_mb_in_slice / width_in_mbs;

src/gen75_mfd.c

@@ -837,6 +837,8 @@ gen75_mfd_avc_slice_state(VADriverContextP ctx,
                          pic_param->seq_fields.bits.mb_adaptive_frame_field_flag);
     int first_mb_in_slice = 0, first_mb_in_next_slice = 0;
     int slice_type;
+    int num_surfaces = 0;
+    int i;
 
     if (slice_param->slice_type == SLICE_TYPE_I ||
         slice_param->slice_type == SLICE_TYPE_SI) {
@@ -863,6 +865,15 @@ gen75_mfd_avc_slice_state(VADriverContextP ctx,
         num_ref_idx_l1 = slice_param->num_ref_idx_l1_active_minus1 + 1;
     }
 
+    /* Don't bind a surface which doesn't exist, that crashes the GPU */
+    for (i = 0; i < ARRAY_ELEMS(gen7_mfd_context->reference_surface); i++)
+        if (gen7_mfd_context->reference_surface[i].surface_id != VA_INVALID_ID)
+            num_surfaces ++;
+    if (num_surfaces == 0) {
+        num_ref_idx_l0 = 0;
+        num_ref_idx_l1 = 0;
+    }
+
     first_mb_in_slice = slice_param->first_mb_in_slice;
     slice_hor_pos = first_mb_in_slice % width_in_mbs;
     slice_ver_pos = first_mb_in_slice / width_in_mbs;

src/gen7_mfd.c

@@ -531,6 +531,8 @@ gen7_mfd_avc_slice_state(VADriverContextP ctx,
                          pic_param->seq_fields.bits.mb_adaptive_frame_field_flag);
     int first_mb_in_slice = 0, first_mb_in_next_slice = 0;
     int slice_type;
+    int num_surfaces = 0;
+    int i;
 
     if (slice_param->slice_type == SLICE_TYPE_I ||
         slice_param->slice_type == SLICE_TYPE_SI) {
@@ -557,6 +559,15 @@ gen7_mfd_avc_slice_state(VADriverContextP ctx,
         num_ref_idx_l1 = slice_param->num_ref_idx_l1_active_minus1 + 1;
     }
 
+    /* Don't bind a surface which doesn't exist, that crashes the GPU */
+    for (i = 0; i < ARRAY_ELEMS(gen7_mfd_context->reference_surface); i++)
+        if (gen7_mfd_context->reference_surface[i].surface_id != VA_INVALID_ID)
+            num_surfaces ++;
+    if (num_surfaces == 0) {
+        num_ref_idx_l0 = 0;
+        num_ref_idx_l1 = 0;
+    }
+
     first_mb_in_slice = slice_param->first_mb_in_slice;
     slice_hor_pos = first_mb_in_slice % width_in_mbs;
     slice_ver_pos = first_mb_in_slice / width_in_mbs;

src/gen8_mfd.c

@@ -614,6 +614,8 @@ gen8_mfd_avc_slice_state(VADriverContextP ctx,
                          pic_param->seq_fields.bits.mb_adaptive_frame_field_flag);
     int first_mb_in_slice = 0, first_mb_in_next_slice = 0;
     int slice_type;
+    int num_surfaces = 0;
+    int i;
 
     if (slice_param->slice_type == SLICE_TYPE_I ||
         slice_param->slice_type == SLICE_TYPE_SI) {
@@ -640,6 +642,15 @@ gen8_mfd_avc_slice_state(VADriverContextP ctx,
         num_ref_idx_l1 = slice_param->num_ref_idx_l1_active_minus1 + 1;
     }
 
+    /* Don't bind a surface which doesn't exist, that crashes the GPU */
+    for (i = 0; i < ARRAY_ELEMS(gen7_mfd_context->reference_surface); i++)
+        if (gen7_mfd_context->reference_surface[i].surface_id != VA_INVALID_ID)
+            num_surfaces ++;
+    if (num_surfaces == 0) {
+        num_ref_idx_l0 = 0;
+        num_ref_idx_l1 = 0;
+    }
+
     first_mb_in_slice = slice_param->first_mb_in_slice;
     slice_hor_pos = first_mb_in_slice % width_in_mbs;
     slice_ver_pos = first_mb_in_slice / width_in_mbs;