Re: [Nouveau] [PATCH] nouveau: explicitly wait on the fence in nouveau_bo_move_m2mf

From: Computer Enthusiastic <computer.enthusiastic@gmail.com>
To: Karol Herbst <kherbst@redhat.com>, Ben Skeggs <bskeggs@redhat.com>
Cc: nouveau@lists.freedesktop.org, Salvatore Bonaccorso <carnil@debian.org>
Subject: Re: [Nouveau] [PATCH] nouveau: explicitly wait on the fence in nouveau_bo_move_m2mf
Date: Tue, 1 Nov 2022 07:44:41 +0100	[thread overview]
Message-ID: <CAHSpYy0HAifr4f+z64h+xFUmMNbB4hCR1r2Z==TsB4WaHatQqg@mail.gmail.com> (raw)
In-Reply-To: <20220819200928.401416-1-kherbst@redhat.com>

Hello,

Il giorno ven 19 ago 2022 alle ore 22:09 Karol Herbst
<kherbst@redhat.com> ha scritto:
>
> It is a bit unlcear to us why that's helping, but it does and unbreaks
> suspend/resume on a lot of GPUs without any known drawbacks.
>
> Cc: stable@vger.kernel.org # v5.15+
> Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/156
> Signed-off-by: Karol Herbst <kherbst@redhat.com>
> ---
>  drivers/gpu/drm/nouveau/nouveau_bo.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
> index 35bb0bb3fe61..126b3c6e12f9 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_bo.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
> @@ -822,6 +822,15 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int evict,
>                 if (ret == 0) {
>                         ret = nouveau_fence_new(chan, false, &fence);
>                         if (ret == 0) {
> +                               /* TODO: figure out a better solution here
> +                                *
> +                                * wait on the fence here explicitly as going through
> +                                * ttm_bo_move_accel_cleanup somehow doesn't seem to do it.
> +                                *
> +                                * Without this the operation can timeout and we'll fallback to a
> +                                * software copy, which might take several minutes to finish.
> +                                */
> +                               nouveau_fence_wait(fence, false, false);
>                                 ret = ttm_bo_move_accel_cleanup(bo,
>                                                                 &fence->base,
>                                                                 evict, false,
> --
> 2.37.1
>

Do you think it could be possible to make the patch land in kernel
5.10.x in the near future ?

Is there something I can do to help it to happen ?

Thanks.