linux-kernel - Re: [PATCH v1 1/5] drm/msm/dp: remove pm_runtime_xxx() from dp

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Date:   Sun, 9 Jul 2023 10:26:18 -0700
From:   Abhinav Kumar <quic_abhinavk@...cinc.com>
To:     Bjorn Andersson <andersson@...nel.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>
CC:     <dri-devel@...ts.freedesktop.org>, <robdclark@...il.com>,
        <sean@...rly.run>, <swboyd@...omium.org>, <dianders@...omium.org>,
        <vkoul@...nel.org>, <daniel@...ll.ch>, <airlied@...il.com>,
        <agross@...nel.org>, <dmitry.baryshkov@...aro.org>,
        <quic_jesszhan@...cinc.com>, <quic_sbillaka@...cinc.com>,
        <marijn.suijten@...ainline.org>, <freedreno@...ts.freedesktop.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/5] drm/msm/dp: remove pm_runtime_xxx() from
 dp_power.c



On 7/8/2023 7:34 PM, Bjorn Andersson wrote:
> On Fri, Jul 07, 2023 at 04:52:19PM -0700, Kuogee Hsieh wrote:
>> Since both pm_runtime_resume() and pm_runtime_suspend() are not
>> populated at dp_pm_ops. Those pm_runtime_get/put() functions within
>> dp_power.c will not have any effects in addition to increase/decrease
>> power counter. Also pm_runtime_xxx() should be executed at top
>> layer.
>>
> 
> Getting/putting the runtime PM state affects the vote for the GDSC. So I
> would suggest that you move this after patch 2, to not create a gap in
> the git history of lacking GDSC votes.
> 
> Regards,
> Bjorn
> 

the mdss_dp node has rpmhpd SC7180_CX in its power domains. the parent 
device has the GDSC.

So just so that I understand this right,  the DP's vote on this will 
still count because the parent's power domain wont get collapsed till 
the child PM votes are removed too?

If so, I see your point and yes it will make sense to move this later to 
avoid the gap.

>> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_power.c | 9 ---------
>>   1 file changed, 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_power.c b/drivers/gpu/drm/msm/dp/dp_power.c
>> index 5cb84ca..ed2f62a 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_power.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_power.c
>> @@ -152,8 +152,6 @@ int dp_power_client_init(struct dp_power *dp_power)
>>   
>>   	power = container_of(dp_power, struct dp_power_private, dp_power);
>>   
>> -	pm_runtime_enable(power->dev);
>> -
>>   	return dp_power_clk_init(power);
>>   }
>>   
>> @@ -162,8 +160,6 @@ void dp_power_client_deinit(struct dp_power *dp_power)
>>   	struct dp_power_private *power;
>>   
>>   	power = container_of(dp_power, struct dp_power_private, dp_power);
>> -
>> -	pm_runtime_disable(power->dev);
>>   }
>>   
>>   int dp_power_init(struct dp_power *dp_power)
>> @@ -173,11 +169,7 @@ int dp_power_init(struct dp_power *dp_power)
>>   
>>   	power = container_of(dp_power, struct dp_power_private, dp_power);
>>   
>> -	pm_runtime_get_sync(power->dev);
>> -
>>   	rc = dp_power_clk_enable(dp_power, DP_CORE_PM, true);
>> -	if (rc)
>> -		pm_runtime_put_sync(power->dev);
>>   
>>   	return rc;
>>   }
>> @@ -189,7 +181,6 @@ int dp_power_deinit(struct dp_power *dp_power)
>>   	power = container_of(dp_power, struct dp_power_private, dp_power);
>>   
>>   	dp_power_clk_enable(dp_power, DP_CORE_PM, false);
>> -	pm_runtime_put_sync(power->dev);
>>   	return 0;
>>   }
>>   
>> -- 
>> 2.7.4
>>