[PATCH v2] drm/amdgpu:No action when VCN PG state is unchanged
James Zhu
jamesz at amd.com
Fri Sep 21 14:22:26 UTC 2018
On 2018-09-21 10:05 AM, Zhu, Rex wrote:
> In my understand, when dpg mode enabled, we don't need to power up/down VCN via SMU and
> Also don't need to set vcn power gate/ungate state.
>
> Just need to enable the dpg mode.
>
> If not true, please correct me.
You are right. Under DPG mode, vcn_v1_0_start is used to setup DPG mode
instead of ungating power.
For code reuse purpose, the function/variable name may have different
connotation under different mode.
James
>
> Best Regards
> Rex
>
>
>
>
>
>> -----Original Message-----
>> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
>> Christian König
>> Sent: Friday, September 21, 2018 8:53 PM
>> To: Zhu, James <James.Zhu at amd.com>; Alex Deucher
>> <alexdeucher at gmail.com>
>> Cc: James Zhu <jzhums at gmail.com>; Zhu, James <James.Zhu at amd.com>;
>> amd-gfx list <amd-gfx at lists.freedesktop.org>
>> Subject: Re: [PATCH v2] drm/amdgpu:No action when VCN PG state is
>> unchanged
>>
>> Am 21.09.2018 um 14:28 schrieb James Zhu:
>>>
>>> On 2018-09-20 01:54 PM, Christian König wrote:
>>>> Am 20.09.2018 um 18:24 schrieb James Zhu:
>>>>>
>>>>> On 2018-09-20 11:49 AM, Alex Deucher wrote:
>>>>>> On Thu, Sep 20, 2018 at 11:27 AM James Zhu <jamesz at amd.com>
>> wrote:
>>>>>>>
>>>>>>> On 2018-09-20 11:14 AM, Alex Deucher wrote:
>>>>>>>> On Thu, Sep 13, 2018 at 4:56 PM James Zhu <jzhums at gmail.com>
>> wrote:
>>>>>>>>> When VCN PG state is unchanged, it is unnecessary to reset power
>>>>>>>>> gate state
>>>>>>>>>
>>>>>>>>> Signed-off-by: James Zhu <James.Zhu at amd.com>
>>>>>>>>> ---
>>>>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h | 1 +
>>>>>>>>> drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c | 12 ++++++++++--
>>>>>>>>> 2 files changed, 11 insertions(+), 2 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>>>>>>> index 0b0b863..d2219ab 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>>>>>>> @@ -69,6 +69,7 @@ struct amdgpu_vcn {
>>>>>>>>> struct amdgpu_ring ring_jpeg;
>>>>>>>>> struct amdgpu_irq_src irq;
>>>>>>>>> unsigned num_enc_rings;
>>>>>>>>> + enum amd_powergating_state cur_state;
>>>>>>>> Does the default value (0) at init time properly reflect the
>>>>>>>> default powergating state? If so,
>>>>>>>> Acked-by: Alex Deucher <alexander.deucher at amd.com>
>>>>>>> Yes, the below code shows it will be set to 0 during driver load
>>>>>>> stage.
>>>>>> Yes, I understand that. Is 0 (AMD_PG_STATE_GATE) what we want as
>>>>>> the default though? The first time the code runs are we going to
>>>>>> do the right thing or is the code going to return early? IIRC, the
>>>>>> hw default is ungated.
>>>>> cur_state is used for tracking driver SW PG state, not HW PG state.
>>>>> I though no matter what HW PG state is after device powers up, when
>>>>> first vcn ring is scheduled to run,
>>>>> begin_use->set_powergating_state->vcn_v1_0_start->ungate
>>>>> power/clock->Boot_VCPU will be tried.
>>>>>
>>>>> For DPG mode, the ungate power/clock , boot VCPU will not actually
>>>>> be activated during start setup stage, and only be activated during
>>>>> ring run stage.
>>>> Mhm, I wonder if it wouldn't be better to have that functionality one
>>>> layer up.
>>>>
>>>> E.g. in amdgpu_device_ip_set_powergating_state so that it applies to
>>>> all IP blocks in the same way.
>>> If necessary, I can add support for IP blocks later.
>> Yeah, agree. In general I'm not doing much with power management, so
>> can't judge if that is a good idea or not.
>>
>> Anyway feel free to add my Acked-by to the patch.
>>
>> Regards,
>> Christian.
>>
>>> James
>>>> But on the other hand the correct solution looks good to me as well,
>>>> so feel free to add my Acked-by as well.
>>>>
>>>> Christian.
>>>>
>>>>> James
>>>>>> Alex
>>>>>>> int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long
>>>>>>> flags)
>>>>>>> ....
>>>>>>> adev = kzalloc(sizeof(struct amdgpu_device), GFP_KERNEL);
>>>>>>>
>>>>>>> struct amdgpu_device {
>>>>>>> ....
>>>>>>> struct amdgpu_vcn vcn;
>>>>>>>
>>>>>>> Best Regards!
>>>>>>> James zhu
>>>>>>>>> };
>>>>>>>>>
>>>>>>>>> int amdgpu_vcn_sw_init(struct amdgpu_device *adev); diff
>>>>>>>>> --git a/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>>>>>>>> index 2664bb2..2cde0b4 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>>>>>>>> @@ -1633,12 +1633,20 @@ static int
>>>>>>>>> vcn_v1_0_set_powergating_state(void *handle,
>>>>>>>>> * revisit this when there is a cleaner line between
>>>>>>>>> * the smc and the hw blocks
>>>>>>>>> */
>>>>>>>>> + int ret;
>>>>>>>>> struct amdgpu_device *adev = (struct amdgpu_device
>>>>>>>>> *)handle;
>>>>>>>>>
>>>>>>>>> + if(state == adev->vcn.cur_state)
>>>>>>>>> + return 0;
>>>>>>>>> +
>>>>>>>>> if (state == AMD_PG_STATE_GATE)
>>>>>>>>> - return vcn_v1_0_stop(adev);
>>>>>>>>> + ret = vcn_v1_0_stop(adev);
>>>>>>>>> else
>>>>>>>>> - return vcn_v1_0_start(adev);
>>>>>>>>> + ret = vcn_v1_0_start(adev);
>>>>>>>>> +
>>>>>>>>> + if(!ret)
>>>>>>>>> + adev->vcn.cur_state = state;
>>>>>>>>> + return ret;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> static const struct amd_ip_funcs vcn_v1_0_ip_funcs = {
>>>>>>>>> --
>>>>>>>>> 2.7.4
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> amd-gfx mailing list
>>>>>>>>> amd-gfx at lists.freedesktop.org
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