[PATCH] drm/amdgpu: avoid over-handle of fence driver fini in s3 test (v2)
Andrey Grodzovsky
andrey.grodzovsky at amd.com
Mon Aug 23 14:41:39 UTC 2021
On 2021-08-23 2:50 a.m., Christian König wrote:
> Good mornings guys,
>
> Andrey has a rather valid concern here, but I think we need to
> approach this from a more high level view.
>
> When hw_fini is called we should make sure that the scheduler can't
> submit any more work to the hardware, because the hw is finalized and
> not expected to response any more.
>
> As far as I can see the cleanest approach would be to stop the
> scheduler in hw_fini and fully clean it up in sw_fini. That would also
> fit quite nicely with how GPU reset is supposed to work I think.
>
> Problem is that this is currently done outside of the fence code for
> the at least the reset case, so before we restructure that we need to
> stick with what we have.
>
> Andrey do you think it would be any problem if we stop the scheduler
> manually in the hot plug case as well?
As long as it's 'parked' inside HW fini - meaning the thread submitting
to HW is done I think it should cover hot unplug as well.
Andrey
>
> Thanks,
> Christian.
>
> Am 23.08.21 um 08:36 schrieb Chen, Guchun:
>> [Public]
>>
>> Hi Andrey,
>>
>> Thanks for your notice. The cause why moving drm_sched_fini to
>> sw_fini is it's a SW behavior and part of SW shutdown, so hw_fini
>> should not touch it. But if the race, that scheduler on the ring
>> possibly keeps submitting jobs which causes un-empty ring is there,
>> possibly we still need to call drm_sched_fini first in hw_fini to
>> stop job submission first.
>>
>> @Koenig, Christian what's your opinion?
>>
>> Regards,
>> Guchun
>>
>> -----Original Message-----
>> From: Alex Deucher <alexdeucher at gmail.com>
>> Sent: Friday, August 20, 2021 2:13 AM
>> To: Mike Lothian <mike at fireburn.co.uk>
>> Cc: Grodzovsky, Andrey <Andrey.Grodzovsky at amd.com>; Chen, Guchun
>> <Guchun.Chen at amd.com>; amd-gfx list <amd-gfx at lists.freedesktop.org>;
>> Gao, Likun <Likun.Gao at amd.com>; Koenig, Christian
>> <Christian.Koenig at amd.com>; Zhang, Hawking <Hawking.Zhang at amd.com>;
>> Deucher, Alexander <Alexander.Deucher at amd.com>
>> Subject: Re: [PATCH] drm/amdgpu: avoid over-handle of fence driver
>> fini in s3 test (v2)
>>
>> Please go ahead. Thanks!
>>
>> Alex
>>
>> On Thu, Aug 19, 2021 at 8:05 AM Mike Lothian <mike at fireburn.co.uk>
>> wrote:
>>> Hi
>>>
>>> Do I need to open a new bug report for this?
>>>
>>> Cheers
>>>
>>> Mike
>>>
>>> On Wed, 18 Aug 2021 at 06:26, Andrey Grodzovsky
>>> <andrey.grodzovsky at amd.com> wrote:
>>>>
>>>> On 2021-08-02 1:16 a.m., Guchun Chen wrote:
>>>>> In amdgpu_fence_driver_hw_fini, no need to call drm_sched_fini to
>>>>> stop scheduler in s3 test, otherwise, fence related failure will
>>>>> arrive after resume. To fix this and for a better clean up, move
>>>>> drm_sched_fini from fence_hw_fini to fence_sw_fini, as it's part of
>>>>> driver shutdown, and should never be called in hw_fini.
>>>>>
>>>>> v2: rename amdgpu_fence_driver_init to amdgpu_fence_driver_sw_init,
>>>>> to keep sw_init and sw_fini paired.
>>>>>
>>>>> Fixes: cd87a6dcf6af drm/amdgpu: adjust fence driver enable sequence
>>>>> Suggested-by: Christian König <christian.koenig at amd.com>
>>>>> Signed-off-by: Guchun Chen <guchun.chen at amd.com>
>>>>> ---
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 5 ++---
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 12 +++++++-----
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 4 ++--
>>>>> 3 files changed, 11 insertions(+), 10 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> index b1d2dc39e8be..9e53ff851496 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> @@ -3646,9 +3646,9 @@ int amdgpu_device_init(struct amdgpu_device
>>>>> *adev,
>>>>>
>>>>> fence_driver_init:
>>>>> /* Fence driver */
>>>>> - r = amdgpu_fence_driver_init(adev);
>>>>> + r = amdgpu_fence_driver_sw_init(adev);
>>>>> if (r) {
>>>>> - dev_err(adev->dev, "amdgpu_fence_driver_init
>>>>> failed\n");
>>>>> + dev_err(adev->dev, "amdgpu_fence_driver_sw_init
>>>>> + failed\n");
>>>>> amdgpu_vf_error_put(adev,
>>>>> AMDGIM_ERROR_VF_FENCE_INIT_FAIL, 0, 0);
>>>>> goto failed;
>>>>> }
>>>>> @@ -3988,7 +3988,6 @@ int amdgpu_device_resume(struct drm_device
>>>>> *dev, bool fbcon)
>>>>> }
>>>>> amdgpu_fence_driver_hw_init(adev);
>>>>>
>>>>> -
>>>>> r = amdgpu_device_ip_late_init(adev);
>>>>> if (r)
>>>>> return r;
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>>>> index 49c5c7331c53..7495911516c2 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>>>> @@ -498,7 +498,7 @@ int amdgpu_fence_driver_init_ring(struct
>>>>> amdgpu_ring *ring,
>>>>> }
>>>>>
>>>>> /**
>>>>> - * amdgpu_fence_driver_init - init the fence driver
>>>>> + * amdgpu_fence_driver_sw_init - init the fence driver
>>>>> * for all possible rings.
>>>>> *
>>>>> * @adev: amdgpu device pointer
>>>>> @@ -509,13 +509,13 @@ int amdgpu_fence_driver_init_ring(struct
>>>>> amdgpu_ring *ring,
>>>>> * amdgpu_fence_driver_start_ring().
>>>>> * Returns 0 for success.
>>>>> */
>>>>> -int amdgpu_fence_driver_init(struct amdgpu_device *adev)
>>>>> +int amdgpu_fence_driver_sw_init(struct amdgpu_device *adev)
>>>>> {
>>>>> return 0;
>>>>> }
>>>>>
>>>>> /**
>>>>> - * amdgpu_fence_driver_fini - tear down the fence driver
>>>>> + * amdgpu_fence_driver_hw_fini - tear down the fence driver
>>>>> * for all possible rings.
>>>>> *
>>>>> * @adev: amdgpu device pointer
>>>>> @@ -531,8 +531,7 @@ void amdgpu_fence_driver_hw_fini(struct
>>>>> amdgpu_device *adev)
>>>>>
>>>>> if (!ring || !ring->fence_drv.initialized)
>>>>> continue;
>>>>> - if (!ring->no_scheduler)
>>>>> - drm_sched_fini(&ring->sched);
>>>>> +
>>>>> /* You can't wait for HW to signal if it's gone */
>>>>> if (!drm_dev_is_unplugged(&adev->ddev))
>>>>> r = amdgpu_fence_wait_empty(ring);
>>>>
>>>> Sorry for late notice, missed this patch. By moving drm_sched_fini
>>>> past amdgpu_fence_wait_empty a race is created as even after you
>>>> waited for all fences on the ring to signal the sw scheduler will
>>>> keep submitting new jobs on the ring and so the ring won't stay empty.
>>>>
>>>> For hot device removal also we want to prevent any access to HW past
>>>> PCI removal in order to not do any MMIO accesses inside the physical
>>>> MMIO range that no longer belongs to this device after it's removal
>>>> by the PCI core. Stopping all the schedulers prevents any MMIO
>>>> accesses done during job submissions and that why drm_sched_fini was
>>>> done as part of amdgpu_fence_driver_hw_fini and not
>>>> amdgpu_fence_driver_sw_fini
>>>>
>>>> Andrey
>>>>
>>>>> @@ -560,6 +559,9 @@ void amdgpu_fence_driver_sw_fini(struct
>>>>> amdgpu_device *adev)
>>>>> if (!ring || !ring->fence_drv.initialized)
>>>>> continue;
>>>>>
>>>>> + if (!ring->no_scheduler)
>>>>> + drm_sched_fini(&ring->sched);
>>>>> +
>>>>> for (j = 0; j <= ring->fence_drv.num_fences_mask; ++j)
>>>>> dma_fence_put(ring->fence_drv.fences[j]);
>>>>> kfree(ring->fence_drv.fences); diff --git
>>>>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>> index 27adffa7658d..9c11ced4312c 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>> @@ -106,7 +106,6 @@ struct amdgpu_fence_driver {
>>>>> struct dma_fence **fences;
>>>>> };
>>>>>
>>>>> -int amdgpu_fence_driver_init(struct amdgpu_device *adev);
>>>>> void amdgpu_fence_driver_force_completion(struct amdgpu_ring
>>>>> *ring);
>>>>>
>>>>> int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring, @@
>>>>> -115,9 +114,10 @@ int amdgpu_fence_driver_init_ring(struct
>>>>> amdgpu_ring *ring,
>>>>> int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
>>>>> struct amdgpu_irq_src *irq_src,
>>>>> unsigned irq_type);
>>>>> +void amdgpu_fence_driver_hw_init(struct amdgpu_device *adev);
>>>>> void amdgpu_fence_driver_hw_fini(struct amdgpu_device *adev);
>>>>> +int amdgpu_fence_driver_sw_init(struct amdgpu_device *adev);
>>>>> void amdgpu_fence_driver_sw_fini(struct amdgpu_device *adev);
>>>>> -void amdgpu_fence_driver_hw_init(struct amdgpu_device *adev);
>>>>> int amdgpu_fence_emit(struct amdgpu_ring *ring, struct
>>>>> dma_fence **fence,
>>>>> unsigned flags);
>>>>> int amdgpu_fence_emit_polling(struct amdgpu_ring *ring,
>>>>> uint32_t *s,
>
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