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

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Message-ID: <af4f9870-3161-87f7-ff4f-1c0ad7869717@loongson.cn>
Date:   Thu, 2 Jul 2020 16:35:48 +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 04:27 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.

>
> 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;
>>   }