From: Daniel Vetter <daniel@ffwll.ch>
To: Rob Clark <robdclark@gmail.com>
Cc: dri-devel@lists.freedesktop.org, Daniel Vetter <daniel@ffwll.ch>,
Rob Clark <robdclark@chromium.org>, Sean Paul <sean@poorly.run>,
David Airlie <airlied@linux.ie>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<linux-arm-msm@vger.kernel.org>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<freedreno@lists.freedesktop.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 22/22] drm/msm: Don't implicit-sync if only a single ring
Date: Mon, 12 Oct 2020 16:40:18 +0200 [thread overview]
Message-ID: <20201012144018.GB438822@phenom.ffwll.local> (raw)
In-Reply-To: <20201012020958.229288-23-robdclark@gmail.com>
On Sun, Oct 11, 2020 at 07:09:49PM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
>
> Any cross-device sync use-cases *must* use explicit sync. And if there
> is only a single ring (no-preemption), everything is FIFO order and
> there is no need to implicit-sync.
>
> Mesa should probably just always use MSM_SUBMIT_NO_IMPLICIT, as behavior
> is undefined when fences are not used to synchronize buffer usage across
> contexts (which is the only case where multiple different priority rings
> could come into play).
Uh does this mean msm is broken on dri2/3 and wayland? Or I'm I just
confused by your commit message?
Since for these protocols we do expect implicit sync accross processes to
work. Even across devices (and nvidia have actually provided quite a bunch
of patches to make this work in i915 - ttm based drivers get this right,
plus dumb scanout drivers using the right helpers also get this all
right).
-Daniel
>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> drivers/gpu/drm/msm/msm_gem_submit.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
> index 3151a0ca8904..c69803ea53c8 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -277,7 +277,7 @@ static int submit_lock_objects(struct msm_gem_submit *submit)
> return ret;
> }
>
> -static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
> +static int submit_fence_sync(struct msm_gem_submit *submit, bool implicit_sync)
> {
> int i, ret = 0;
>
> @@ -297,7 +297,7 @@ static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
> return ret;
> }
>
> - if (no_implicit)
> + if (!implicit_sync)
> continue;
>
> ret = msm_gem_sync_object(&msm_obj->base, submit->ring->fctx,
> @@ -768,7 +768,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
> if (ret)
> goto out;
>
> - ret = submit_fence_sync(submit, !!(args->flags & MSM_SUBMIT_NO_IMPLICIT));
> + ret = submit_fence_sync(submit, (gpu->nr_rings > 1) &&
> + !(args->flags & MSM_SUBMIT_NO_IMPLICIT));
> if (ret)
> goto out;
>
> --
> 2.26.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2020-10-12 14:40 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 2:09 [PATCH 00/14] drm/msm: de-struct_mutex-ification Rob Clark
2020-10-12 2:09 ` [PATCH v2 01/22] drm/msm/gem: Add obj->lock wrappers Rob Clark
2020-10-12 2:09 ` [PATCH v2 02/22] drm/msm/gem: Rename internal get_iova_locked helper Rob Clark
2020-10-12 2:09 ` [PATCH v2 03/22] drm/msm/gem: Move prototypes to msm_gem.h Rob Clark
2020-10-12 2:09 ` [PATCH v2 04/22] drm/msm/gem: Add some _locked() helpers Rob Clark
2020-10-12 2:09 ` [PATCH v2 05/22] drm/msm/gem: Move locking in shrinker path Rob Clark
2020-10-12 2:09 ` [PATCH v2 06/22] drm/msm/submit: Move copy_from_user ahead of locking bos Rob Clark
2020-10-12 2:09 ` [PATCH v2 07/22] drm/msm: Do rpm get sooner in the submit path Rob Clark
2020-10-12 14:35 ` Daniel Vetter
2020-10-12 15:43 ` Rob Clark
2020-10-20 9:07 ` Viresh Kumar
2020-10-20 10:56 ` Daniel Vetter
2020-10-20 11:24 ` Viresh Kumar
2020-10-20 11:42 ` Daniel Vetter
2020-10-20 14:13 ` Rob Clark
2020-10-22 8:06 ` Viresh Kumar
2020-10-25 17:39 ` Rob Clark
2020-10-27 11:35 ` Viresh Kumar
2020-11-03 5:47 ` Viresh Kumar
2020-11-03 16:50 ` Rob Clark
2020-11-04 3:03 ` Viresh Kumar
2020-11-05 19:24 ` Rob Clark
2020-11-06 7:16 ` Viresh Kumar
2020-11-17 10:03 ` Viresh Kumar
2020-11-17 17:02 ` Rob Clark
2020-11-18 5:28 ` Viresh Kumar
2020-11-18 16:53 ` Rob Clark
2020-11-19 6:05 ` Viresh Kumar
2020-12-07 6:16 ` Viresh Kumar
2020-12-16 5:22 ` Viresh Kumar
2020-10-12 2:09 ` [PATCH v2 08/22] drm/msm/gem: Switch over to obj->resv for locking Rob Clark
2020-10-12 2:09 ` [PATCH v2 09/22] drm/msm: Use correct drm_gem_object_put() in fail case Rob Clark
2020-10-12 2:09 ` [PATCH v2 10/22] drm/msm: Drop chatty trace Rob Clark
2020-10-12 2:09 ` [PATCH v2 11/22] drm/msm: Move update_fences() Rob Clark
2020-10-12 2:09 ` [PATCH v2 12/22] drm/msm: Add priv->mm_lock to protect active/inactive lists Rob Clark
2020-10-12 2:09 ` [PATCH v2 13/22] drm/msm: Document and rename preempt_lock Rob Clark
2020-10-12 2:09 ` [PATCH v2 14/22] drm/msm: Protect ring->submits with it's own lock Rob Clark
2020-10-12 2:09 ` [PATCH v2 15/22] drm/msm: Refcount submits Rob Clark
2020-10-12 2:09 ` [PATCH v2 16/22] drm/msm: Remove obj->gpu Rob Clark
2020-10-12 2:09 ` [PATCH v2 17/22] drm/msm: Drop struct_mutex from the retire path Rob Clark
2020-10-12 2:09 ` [PATCH v2 18/22] drm/msm: Drop struct_mutex in free_object() path Rob Clark
2020-10-12 2:09 ` [PATCH v2 19/22] drm/msm: remove msm_gem_free_work Rob Clark
2020-10-12 2:09 ` [PATCH v2 20/22] drm/msm: drop struct_mutex in madvise path Rob Clark
2020-10-12 2:09 ` [PATCH v2 21/22] drm/msm: Drop struct_mutex in shrinker path Rob Clark
2020-10-12 2:09 ` [PATCH v2 22/22] drm/msm: Don't implicit-sync if only a single ring Rob Clark
2020-10-12 14:40 ` Daniel Vetter [this message]
2020-10-12 15:07 ` Rob Clark
2020-10-13 11:08 ` Daniel Vetter
2020-10-13 16:15 ` [Freedreno] " Rob Clark
2020-10-15 8:22 ` Daniel Vetter
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