linux-kernel - Re: [PATCH 4/4] drm/nouveau: Check dma

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Message-ID: <aAo96dnXwFBxx8as@cassiopeiae>
Date: Thu, 24 Apr 2025 15:34:33 +0200
From: Danilo Krummrich <dakr@...nel.org>
To: phasta@...nel.org, maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org, tzimmermann@...e.de
Cc: Lyude Paul <lyude@...hat.com>, David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>,
	dri-devel@...ts.freedesktop.org, nouveau@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
	linaro-mm-sig@...ts.linaro.org
Subject: Re: [PATCH 4/4] drm/nouveau: Check dma_fence in canonical way

(+ drm-misc maintainers)

On Thu, Apr 24, 2025 at 03:25:55PM +0200, Philipp Stanner wrote:
> On Thu, 2025-04-24 at 15:24 +0200, Danilo Krummrich wrote:
> > On 4/24/25 3:02 PM, Philipp Stanner wrote:
> > > In nouveau_fence_done(), a fence is checked for being signaled by
> > > manually evaluating the base fence's bits. This can be done in a
> > > canonical manner through dma_fence_is_signaled().
> > > 
> > > Replace the bit-check with dma_fence_is_signaled().
> > > 
> > > Signed-off-by: Philipp Stanner <phasta@...nel.org>
> > > ---
> > >   drivers/gpu/drm/nouveau/nouveau_fence.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c
> > > b/drivers/gpu/drm/nouveau/nouveau_fence.c
> > > index fb9811938c82..d5654e26d5bc 100644
> > > --- a/drivers/gpu/drm/nouveau/nouveau_fence.c
> > > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
> > > @@ -253,7 +253,7 @@ nouveau_fence_done(struct nouveau_fence *fence)
> > >   	struct nouveau_channel *chan;
> > >   	unsigned long flags;
> > >   
> > > -	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence-
> > > >base.flags))
> > > +	if (dma_fence_is_signaled(&fence->base))
> > 
> > This is only correct with commit bbe5679f30d7 ("drm/nouveau: Fix
> > WARN_ON in
> > nouveau_fence_context_kill()") from drm-misc-fixes, correct?
> 
> Yup. Otherwise, this series can't be merged anyways, because patch 1
> depends on it.
> 
> The cover letter says so: "This series is based on this partially
> merged series: [1]"

Well, the series may be based on commit bbe5679f30d7, but all patches from the
series can still be applied independently.

Only patch 4 depends on this commit in terms of correctness.

But that's fine, I think we can get drm-misc-fixes (or the next -rc) backmerged
into drm-misc-next.