lib/gt: Replace hanging instruction

First try an illegal instruction before the infinite loop to try and
trigger a gpu hang more gracefully as the infinite loop is causing some
older machines issues as the GPU hogs the entire systems and makes the
machine laggy, unresponsive for long periods.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/igt_gt.c b/lib/igt_gt.c
index ac3ab773..95d74a0c 100644
--- a/lib/igt_gt.c
+++ b/lib/igt_gt.c
@@ -137,7 +137,7 @@ igt_hang_ring_t igt_hang_ctx(int fd,
 	struct drm_i915_gem_execbuffer2 execbuf;
 	struct drm_i915_gem_exec_object2 exec;
 	struct local_i915_gem_context_param param;
-	uint32_t b[8];
+	uint32_t b[16];
 	unsigned ban;
 	unsigned len;
 
@@ -181,21 +181,21 @@ igt_hang_ring_t igt_hang_ctx(int fd,
 	exec.relocs_ptr = (uintptr_t)&reloc;
 
 	memset(b, 0xc5, sizeof(b));
+	b[0] = 0xffffffff;
 	len = 2;
 	if (intel_gen(intel_get_drm_devid(fd)) >= 8)
 		len++;
-	b[0] = MI_BATCH_BUFFER_START | (len - 2);
-	b[len] = MI_BATCH_BUFFER_END;
-	b[len+1] = MI_NOOP;
+	b[1] = MI_BATCH_BUFFER_START | (len - 2);
+	b[1+len] = MI_BATCH_BUFFER_END;
+	b[2+len] = MI_NOOP;
 	gem_write(fd, exec.handle, 0, b, sizeof(b));
 
-	reloc.offset = 4;
+	reloc.offset = 8;
 	reloc.target_handle = exec.handle;
 	reloc.read_domains = I915_GEM_DOMAIN_COMMAND;
 
 	execbuf.buffers_ptr = (uintptr_t)&exec;
 	execbuf.buffer_count = 1;
-	execbuf.batch_len = sizeof(b);
 	execbuf.flags = ring;
 	i915_execbuffer2_set_context_id(execbuf, ctx);
 	gem_execbuf(fd, &execbuf);