On 5/20/25 18:44, Alex Bennée wrote:
> Yiwei Zhang <zzyi...@gmail.com> writes:
>
>> Venus and later native contexts have their own fence context along with
>> multiple timelines within. Fences wtih VIRTIO_GPU_FLAG_INFO_RING_IDX in
>> the flags must be dispatched to be created on the target context. Fence
>> signaling also has to be handled on the specific timeline within that
>> target context.
>>
>> Before this change, venus fencing is completely broken if the host
>> driver doesn't support implicit fencing with external memory objects.
>> Frames can go backwards along with random artifacts on screen if the
>> host driver doesn't attach an implicit fence to the render target. The
>> symptom could be hidden by certain guest wsi backend that waits on a
>> venus native VkFence object for the actual payload with limited present
>> modes or under special configs. e.g. x11 mailbox or xwayland.
>>
>> After this change, everything related to venus fencing starts making
>> sense. Confirmed this via guest and host side perfetto tracing.
>>
>> Changes since v1:
>> - Minor commit msg updates based on feedbacks from BALATON
>>
>> Cc: qemu-sta...@nongnu.org
>> Fixes: 94d0ea1c1928 ("virtio-gpu: Support Venus context")
>> Signed-off-by: Yiwei Zhang <zzyi...@gmail.com>
>
> Queued to virtio-gpu/next (in maintainer/may-2025), thanks.
> <snip>
>
Wanted to notify you about the patch after giving it a test, but you
beat me to it. Thanks for taking the care. Tested now, Steam games work.
Tested-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
--
Best regards,
Dmitry
