[PATCH 2/2] drm/amdgpu: allow APU to send power gate message when dpm is disabled

[Lazar, Lijo]

On 12/6/2021 8:19 AM, Yu, Lang wrote:
> [Public]
> 
> 
> 
>> -----Original Message-----
>> From: Lazar, Lijo <Lijo.Lazar at amd.com>
>> Sent: Friday, December 3, 2021 5:52 PM
>> To: Yu, Lang <Lang.Yu at amd.com>; amd-gfx at lists.freedesktop.org
>> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; Huang, Ray
>> <Ray.Huang at amd.com>
>> Subject: Re: [PATCH 2/2] drm/amdgpu: allow APU to send power gate message
>> when dpm is disabled
>>
>>
>>
>> On 12/3/2021 12:24 PM, Lang Yu wrote:
>>> The general hw fini sequence is SMU-> ... ->SDMA-> ...
>>> We need to send power gate message to power off SDMA(in SDMA
>>> hw_fini()) afer dpm is disabled(in SMU hw_fini()). Allow that for APU.
>>
>> This message is not right. In APUs there is no message provided by FW to
>> enable/disable DPM, it is done in BIOS. Rephrase to something like after smu
>> hw_fini is completed.
> 
> It is power on/off SDMA message. Not enable/disable DPM.
> 
Bad choice of word :) I didn't mean FW message, it was about this line 
in "commit message" - "afer dpm is disabled".

>>>
>>> Signed-off-by: Lang Yu <lang.yu at amd.com>
>>> ---
>>>    drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
>>> b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
>>> index 2d718c30c8eb..285a237f3605 100644
>>> --- a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
>>> +++ b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
>>> @@ -277,7 +277,7 @@ static int smu_dpm_set_power_gate(void *handle,
>>>    	struct smu_context *smu = handle;
>>>    	int ret = 0;
>>>
>>> -	if (!smu->pm_enabled || !smu->adev->pm.dpm_enabled) {
>>> +	if (!smu->pm_enabled || (!smu->is_apu &&
>>> +!smu->adev->pm.dpm_enabled)) {
>>
>>
>> This check was there before also, only the WARN is added. That means it was
>> skipping sending messages in APUs also and so far this was working fine (until this
>> gets noticed because of the warning).
>>
>> Now this would try to send the message to APU without any check. That doesn't
>> look good. Ideal way should be to fix the sequence. Otherwise, suggest to do
>> something like below as the last step of smu hw cleanup rather than sending the
>> message blindly.
>>
>> 	if (smu->is_apu)
>> 		smu->pm.dpm_enabled = smu_is_dpm_running(smu);
> 
> smu_is_dpm_running(smu) will cause errors in suspend.
> 
That is interesting. What is the error you get?

Thanks,
Lijo

> Here we just  send some IP power on/off messages.
> Is it necessary to enable DPM to send such messages?
> 
> Regards,
> Lang
> 
>> Thanks,
>> Lijo
>>
>>>    		dev_WARN(smu->adev->dev,
>>>    			 "SMU uninitialized but power %s requested for %u!\n",
>>>    			 gate ? "gate" : "ungate", block_type);
>>>