Re: [PATCH v3] drm/panfrost: Move the GPU reset bits outside the timeout handler

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue, 3 Nov 2020 11:25:40 +0100
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, Nov 03, 2020 at 09:13:47AM +0100, Boris Brezillon wrote:
> > We've fixed many races in panfrost_job_timedout() but some remain.
> > Instead of trying to fix it again, let's simplify the logic and move
> > the reset bits to a separate work scheduled when one of the queue
> > reports a timeout.
> > 
> > v3:
> > - Replace the atomic_cmpxchg() by an atomic_xchg() (Robin Murphy)
> > - Add Steven's R-b
> > 
> > v2:
> > - Use atomic_cmpxchg() to conditionally schedule the reset work (Steven Price)
> > 
> > Fixes: 1a11a88cfd9a ("drm/panfrost: Fix job timeout handling")
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> > Reviewed-by: Steven Price <steven.price@arm.com>  
> 
> Sprinkling the dma_fence annotations over this would be really nice ...

You mean something like that?

--->8---
From 4f90ee2972eaec0332833ff6f9ea078acbfa899a Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@collabora.com>
Date: Tue, 3 Nov 2020 12:01:09 +0100
Subject: [PATCH] drm/panfrost: Annotate dma_fence signalling

Annotate dma_fence signalling to help lockdep catch deadlocks.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_job.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 569a099dc10e..046cb3677332 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -482,7 +482,9 @@ static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
 
 		if (status & JOB_INT_MASK_DONE(j)) {
 			struct panfrost_job *job;
+			bool cookie;
 
+			cookie = dma_fence_begin_signalling();
 			spin_lock(&pfdev->js->job_lock);
 			job = pfdev->jobs[j];
 			/* Only NULL if job timeout occurred */
@@ -496,6 +498,7 @@ static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
 				pm_runtime_put_autosuspend(pfdev->dev);
 			}
 			spin_unlock(&pfdev->js->job_lock);
+			dma_fence_end_signalling(cookie);
 		}
 
 		status &= ~mask;