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

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Message-ID: <897b806e-dba8-710f-6b62-2493e3033417@loongson.cn>
Date:   Thu, 2 Jul 2020 17:51:53 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Christian König <christian.koenig@....com>,
        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

On 07/02/2020 04:39 PM, Christian König wrote:
> Am 02.07.20 um 10:35 schrieb Tiezhu Yang:
>> On 07/02/2020 04:27 PM, Christian König wrote:
>>> 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.
>>
>> Should I split this patch into two patches and then send v3?
>> If yes, I will do it soon.
>
> For me it's ok to merge it like it is now.
>
> Only Alex could insists to split the patches, but then he will 
> probably do it himself.

OK, then I will not send v3.

>
> Thanks for the help,
> Christian.
>
>>
>>>
>>> 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;
>>>>   }
>>