[igt-dev] [PATCH i-g-t 1/7] lib/gem_submission: Add kernel exec object alignment capability

[Dixit, Ashutosh]

On Thu, 07 Oct 2021 23:54:26 -0700, Zbigniew Kempczyński wrote:
>
> +bool gem_allows_passing_alignment(int fd)
> +{
> +	struct drm_i915_gem_exec_object2 obj = {
> +		.handle = gem_create(fd, 4096),
> +	};
> +	struct drm_i915_gem_execbuffer2 execbuf = {
> +		.buffers_ptr = to_user_pointer(&obj),
> +		.buffer_count = 1,
> +	};
> +	bool ret;
> +	const uint32_t bbe = MI_BATCH_BUFFER_END;
> +
> +	gem_write(fd, obj.handle, 0, &bbe, sizeof(bbe));
> +	gem_execbuf(fd, &execbuf);
> +
> +	obj.alignment = 0x2000;

8K? Shouldn't this be less than 4K?

> +	ret = __gem_execbuf(fd, &execbuf) == 0;
> +	gem_close(fd, obj.handle);
> +
> +	return ret;
> +}