radv: make sure to not submit any IBs when RADV_FORCE_FAMILY is set

To prevent GPU hangs.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3654>

docs/envvars.html

@@ -583,6 +583,8 @@ Mesa EGL supports different sets of environment variables.  See the
    <dd>disable memory shaders cache</dd>
    <dt><code>nongg</code></dt>
    <dd>disable NGG for GFX10+</dd>
+   <dt><code>noop</code></dt>
+   <dd>do not submit any IBs</dd>
    <dt><code>nooutoforder</code></dt>
    <dd>disable out-of-order rasterization</dd>
    <dt><code>noshaderballot</code></dt>

src/amd/vulkan/radv_debug.h

@@ -57,6 +57,7 @@ enum {
 	RADV_DEBUG_ALL_ENTRYPOINTS   = 0x4000000,
 	RADV_DEBUG_DUMP_META_SHADERS = 0x8000000,
 	RADV_DEBUG_NO_MEMORY_CACHE   = 0x10000000,
+	RADV_DEBUG_NOOP              = 0x20000000,
 };
 
 enum {

src/amd/vulkan/radv_device.c

@@ -312,6 +312,8 @@ radv_handle_env_var_force_family(struct radv_physical_device *device)
 			else
 				device->rad_info.chip_class = GFX6;
 
+			/* Don't submit any IBs. */
+			device->instance->debug_flags |= RADV_DEBUG_NOOP;
 			return;
 		}
 	}
@@ -560,6 +562,7 @@ static const struct debug_control radv_debug_options[] = {
 	{"allentrypoints", RADV_DEBUG_ALL_ENTRYPOINTS},
 	{"metashaders", RADV_DEBUG_DUMP_META_SHADERS},
 	{"nomemorycache", RADV_DEBUG_NO_MEMORY_CACHE},
+	{"noop", RADV_DEBUG_NOOP},
 	{NULL, 0}
 };
 

src/amd/vulkan/winsys/amdgpu/radv_amdgpu_cs.c

@@ -1235,6 +1235,9 @@ static int radv_amdgpu_winsys_cs_submit(struct radeon_winsys_ctx *_ctx,
 	struct radv_amdgpu_ctx *ctx = radv_amdgpu_ctx(_ctx);
 	int ret;
 
+	if (cs->ws->noop)
+		abort();
+
 	assert(sem_info);
 	if (!cs->ws->use_ib_bos) {
 		ret = radv_amdgpu_winsys_cs_submit_sysmem(_ctx, queue_idx, sem_info, bo_list, cs_array,

src/amd/vulkan/winsys/amdgpu/radv_amdgpu_winsys.c

@@ -189,6 +189,7 @@ radv_amdgpu_winsys_create(int fd, uint64_t debug_flags, uint64_t perftest_flags)
 
 	ws->use_local_bos = perftest_flags & RADV_PERFTEST_LOCAL_BOS;
 	ws->zero_all_vram_allocs = debug_flags & RADV_DEBUG_ZERO_VRAM;
+	ws->noop = debug_flags & RADV_DEBUG_NOOP;
 	ws->batchchain = !(perftest_flags & RADV_PERFTEST_NO_BATCHCHAIN);
 	list_inithead(&ws->global_bo_list);
 	pthread_mutex_init(&ws->global_bo_list_lock, NULL);

src/amd/vulkan/winsys/amdgpu/radv_amdgpu_winsys.h

@@ -48,6 +48,7 @@ struct radv_amdgpu_winsys {
 	bool use_ib_bos;
 	bool zero_all_vram_allocs;
 	bool use_local_bos;
+	bool noop;
 	unsigned num_buffers;
 
 	pthread_mutex_t global_bo_list_lock;