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

[Yu, Lang]

[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.

>>
>> 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.

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);
>>