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From: Grigori Goronzy <greg@chown.ath.cx>
To: "Christian König" <deathsimple@vodafone.de>,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/radeon: fix semaphore value init
Date: Sun, 07 Sep 2014 19:41:44 +0200	[thread overview]
Message-ID: <540C98D8.1020500@chown.ath.cx> (raw)
In-Reply-To: <1410084412-2541-1-git-send-email-deathsimple@vodafone.de>


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On 07.09.2014 12:06, Christian König wrote:
> From: Christian König <christian.koenig@amd.com>
> 
> Semaphore values have 64 bits, not 32. This fixes a very subtle bug
> that disables synchronization when the upper 32bits wasn't zero.
>

So essentially, half the semaphore values were never properly
initialized and some loads with a lot of semaphore synchronization going
on tried to use the uninitialized semaphores. I think the description in
the commit could be improved according to that.

I didn't get any DMA L2T copy hangs with semaphores disabled completely,
but unfortunately this doesn't fix the hangs.

Anyway,
Reviewed-By: Grigori Goronzy <greg@chown.ath.cx>

Grigori

> Signed-off-by: Christian König <christian.koenig@amd.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/radeon/radeon_semaphore.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_semaphore.c b/drivers/gpu/drm/radeon/radeon_semaphore.c
> index 56d9fd6..abd6753 100644
> --- a/drivers/gpu/drm/radeon/radeon_semaphore.c
> +++ b/drivers/gpu/drm/radeon/radeon_semaphore.c
> @@ -34,7 +34,7 @@
>  int radeon_semaphore_create(struct radeon_device *rdev,
>  			    struct radeon_semaphore **semaphore)
>  {
> -	uint32_t *cpu_addr;
> +	uint64_t *cpu_addr;
>  	int i, r;
>  
>  	*semaphore = kmalloc(sizeof(struct radeon_semaphore), GFP_KERNEL);
> 



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  reply	other threads:[~2014-09-07 17:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-07 10:06 [PATCH] drm/radeon: fix semaphore value init Christian König
2014-09-07 17:41 ` Grigori Goronzy [this message]
2014-09-08  8:14   ` Christian König
2014-09-08 17:21 ` Alex Deucher

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