Nouveau - Sep 2014 - [PATCH] drm/nv84+: fix fence context seqno's

This fixes a regression introduced by "drm/nouveau: rework to new fence
interface"
(commit 29ba89b2371d466).

The fence sequence should not be reset after creation, the old value is used
instead.
On destruction the final value is written, to prevent another source of
accidental
wraparound in case of a channel being destroyed after a hang, and unblocking any
other
channel that may wait on the about-to-be-deleted channel to signal.

I'm nothing if not optimistic about any hope of recovery from that. ;-)

Reported-by: Ted Percival <ted at tedp.id.au>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
diff --git a/drivers/gpu/drm/nouveau/nv84_fence.c
b/drivers/gpu/drm/nouveau/nv84_fence.c
index 7b372a68aa4e..4138db4d8291 100644
--- a/drivers/gpu/drm/nouveau/nv84_fence.c
+++ b/drivers/gpu/drm/nouveau/nv84_fence.c
@@ -120,6 +120,7 @@ nv84_fence_context_del(struct nouveau_channel *chan)
 		nouveau_bo_vma_del(bo, &fctx->dispc_vma[i]);
 	}
 
+	nouveau_bo_wr32(priv->bo, chan->chid * 16 / 4, fctx->base.sequence);
 	nouveau_bo_vma_del(priv->bo, &fctx->vma_gart);
 	nouveau_bo_vma_del(priv->bo, &fctx->vma);
 	nouveau_fence_context_del(&fctx->base);
@@ -159,8 +160,6 @@ nv84_fence_context_new(struct nouveau_channel *chan)
 		ret = nouveau_bo_vma_add(bo, cli->vm, &fctx->dispc_vma[i]);
 	}
 
-	nouveau_bo_wr32(priv->bo, chan->chid * 16/4, 0x00000000);
-
 	if (ret)
 		nv84_fence_context_del(chan);
 	return ret;

On 09/22/2014 03:08 AM, Maarten Lankhorst wrote:
> This fixes a regression introduced by "drm/nouveau: rework to new
fence interface"
> (commit 29ba89b2371d466).
> 
> The fence sequence should not be reset after creation, the old value is
used instead.
> On destruction the final value is written, to prevent another source of
accidental
> wraparound in case of a channel being destroyed after a hang, and
unblocking any other
> channel that may wait on the about-to-be-deleted channel to signal.
> 
> I'm nothing if not optimistic about any hope of recovery from that. ;-)
> 
> Reported-by: Ted Percival <ted at tedp.id.au>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
> ---
> diff --git a/drivers/gpu/drm/nouveau/nv84_fence.c
b/drivers/gpu/drm/nouveau/nv84_fence.c
> index 7b372a68aa4e..4138db4d8291 100644
> --- a/drivers/gpu/drm/nouveau/nv84_fence.c
> +++ b/drivers/gpu/drm/nouveau/nv84_fence.c
> @@ -120,6 +120,7 @@ nv84_fence_context_del(struct nouveau_channel *chan)
>  		nouveau_bo_vma_del(bo, &fctx->dispc_vma[i]);
>  	}
>  
> +	nouveau_bo_wr32(priv->bo, chan->chid * 16 / 4,
fctx->base.sequence);
>  	nouveau_bo_vma_del(priv->bo, &fctx->vma_gart);
>  	nouveau_bo_vma_del(priv->bo, &fctx->vma);
>  	nouveau_fence_context_del(&fctx->base);
> @@ -159,8 +160,6 @@ nv84_fence_context_new(struct nouveau_channel *chan)
>  		ret = nouveau_bo_vma_add(bo, cli->vm, &fctx->dispc_vma[i]);
>  	}
>  
> -	nouveau_bo_wr32(priv->bo, chan->chid * 16/4, 0x00000000);
> -
>  	if (ret)
>  		nv84_fence_context_del(chan);
>  	return ret;
> 
This works, thanks :-)

Tested-by: Ted Percival <ted at tedp.id.au>

On Tue, Sep 23, 2014 at 2:23 AM, Ted Percival <ted at tedp.id.au>
wrote:
> On 09/22/2014 03:08 AM, Maarten Lankhorst wrote:
>> This fixes a regression introduced by "drm/nouveau: rework to new
fence interface"
>> (commit 29ba89b2371d466).
>>
>> The fence sequence should not be reset after creation, the old value is
used instead.
>> On destruction the final value is written, to prevent another source of
accidental
>> wraparound in case of a channel being destroyed after a hang, and
unblocking any other
>> channel that may wait on the about-to-be-deleted channel to signal.
>>
>> I'm nothing if not optimistic about any hope of recovery from that.
;-)
>>
>> Reported-by: Ted Percival <ted at tedp.id.au>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at
canonical.com>
Acked-by: Ben Skeggs <bskeggs at redhat.com>

I'm still seeing issues with suspend, even with this patch, and the
one you pastebinned recently.
>> ---
>> diff --git a/drivers/gpu/drm/nouveau/nv84_fence.c
b/drivers/gpu/drm/nouveau/nv84_fence.c
>> index 7b372a68aa4e..4138db4d8291 100644
>> --- a/drivers/gpu/drm/nouveau/nv84_fence.c
>> +++ b/drivers/gpu/drm/nouveau/nv84_fence.c
>> @@ -120,6 +120,7 @@ nv84_fence_context_del(struct nouveau_channel
*chan)
>>               nouveau_bo_vma_del(bo, &fctx->dispc_vma[i]);
>>       }
>>
>> +     nouveau_bo_wr32(priv->bo, chan->chid * 16 / 4,
fctx->base.sequence);
>>       nouveau_bo_vma_del(priv->bo, &fctx->vma_gart);
>>       nouveau_bo_vma_del(priv->bo, &fctx->vma);
>>       nouveau_fence_context_del(&fctx->base);
>> @@ -159,8 +160,6 @@ nv84_fence_context_new(struct nouveau_channel
*chan)
>>               ret = nouveau_bo_vma_add(bo, cli->vm,
&fctx->dispc_vma[i]);
>>       }
>>
>> -     nouveau_bo_wr32(priv->bo, chan->chid * 16/4, 0x00000000);
>> -
>>       if (ret)
>>               nv84_fence_context_del(chan);
>>       return ret;
>>
>
> This works, thanks :-)
>
> Tested-by: Ted Percival <ted at tedp.id.au>
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