linux-kernel - Re: [PATCH v2] gpu/drm: Remove debug info about CPU address

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Message-ID: <85c81fa9-2994-d861-0690-a79600ed84b3@amd.com>
Date:   Thu, 2 Jul 2020 10:27:36 +0200
From:   Christian König <christian.koenig@....com>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>, alexander.deucher@....com
Cc:     amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] gpu/drm: Remove debug info about CPU address

Am 02.07.20 um 04:27 schrieb Tiezhu Yang:
> When I update the latest kernel, I see the following "____ptrval____" boot
> messages.
>
> [    1.872600] radeon 0000:01:05.0: fence driver on ring 0 use gpu addr 0x0000000048000c00 and cpu addr 0x(____ptrval____)
> [    1.879095] radeon 0000:01:05.0: fence driver on ring 5 use gpu addr 0x0000000040056038 and cpu addr 0x(____ptrval____)
>
> Both radeon_fence_driver_start_ring() and amdgpu_fence_driver_start_ring()
> have the similar issue, there exists the following two methods to solve it:
> (1) Use "%pK" instead of "%p" so that the CPU address can be printed when
> the kptr_restrict sysctl is set to 1.
> (2) Just completely drop the CPU address suggested by Christian, because
> the CPU address was useful in the past, but isn't any more. We now have a
> debugfs file to read the current fence values.
>
> Since the CPU address is not much useful, just remove the debug info about
> CPU address.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>

Splitting it into one patch for radeon and one for amdgpu might be nice 
to have.

But either way Reviewed-by: Christian König <christian.koenig@....com> 
for the patch.

Thanks,
Christian.

> ---
>
> v2:
>    - Just remove the debug info about CPU address suggested by Christian
>    - Modify the patch subject and update the commit message
>
>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 5 ++---
>   drivers/gpu/drm/radeon/radeon_fence.c     | 4 ++--
>   2 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> index d878fe7..a29f2f9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> @@ -422,9 +422,8 @@ int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
>   	ring->fence_drv.irq_type = irq_type;
>   	ring->fence_drv.initialized = true;
>   
> -	DRM_DEV_DEBUG(adev->dev, "fence driver on ring %s use gpu addr "
> -		      "0x%016llx, cpu addr 0x%p\n", ring->name,
> -		      ring->fence_drv.gpu_addr, ring->fence_drv.cpu_addr);
> +	DRM_DEV_DEBUG(adev->dev, "fence driver on ring %s use gpu addr 0x%016llx\n",
> +		      ring->name, ring->fence_drv.gpu_addr);
>   	return 0;
>   }
>   
> diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
> index 43f2f93..8735bf2 100644
> --- a/drivers/gpu/drm/radeon/radeon_fence.c
> +++ b/drivers/gpu/drm/radeon/radeon_fence.c
> @@ -865,8 +865,8 @@ int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
>   	}
>   	radeon_fence_write(rdev, atomic64_read(&rdev->fence_drv[ring].last_seq), ring);
>   	rdev->fence_drv[ring].initialized = true;
> -	dev_info(rdev->dev, "fence driver on ring %d use gpu addr 0x%016llx and cpu addr 0x%p\n",
> -		 ring, rdev->fence_drv[ring].gpu_addr, rdev->fence_drv[ring].cpu_addr);
> +	dev_info(rdev->dev, "fence driver on ring %d use gpu addr 0x%016llx\n",
> +		 ring, rdev->fence_drv[ring].gpu_addr);
>   	return 0;
>   }
>