[igt-dev] [PATCH] tests/kms_prime: Filter out devices that can't import buffers.

[Petri Latvala]

On Mon, Jun 14, 2021 at 12:41:34PM -0400, Mark Yacoub wrote:
> Some devices such as amdgpu do not support imported buffers.
> Filter out those devices.
> Tested on Zork with chromeos-kernel-5_4.
> 
> Signed-off-by: Mark Yacoub <markyacoub at chromium.org>
> ---
>  tests/kms_prime.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/kms_prime.c b/tests/kms_prime.c
> index 8cb2ca2a..480c7eb4 100644
> --- a/tests/kms_prime.c
> +++ b/tests/kms_prime.c
> @@ -249,6 +249,16 @@ static void test_crc(int exporter_fd, int importer_fd)
>  	igt_display_fini(&display);
>  }
>  
> +/* The test attempts to import the buffer object from one device to another.
> + * Filter out devices that aren't capable of doing this.
> + */
> +bool does_device_support_dmabuf_import(int fd) {
> +	/* AMDGPU uses VRAM. Any use of the fb will migrate it to VRAM, which is not sensible for
> +	 * an imported dma-buf.
> +	 */
> +	return !is_amdgpu_device(fd);
> +}

How is real (aka non-IGT) userspace supposed to handle this? Will they
need to check if the device is an AMD device before deciding whether
to import?

What happens in this test without this patch?

+Cc Arek. My initial impression for this is that the kernel should
take care of the idiosyncracies but I'm lacking the big picture.


-- 
Petri Latvala