linux-kernel - Re: [PATCH v6 5/6] media: venus: core: Add support for opp tables/perf voting

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Date:   Mon, 29 Jun 2020 16:19:08 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     Stanimir Varbanov <stanimir.varbanov@...aro.org>,
        bjorn.andersson@...aro.org, agross@...nel.org, robdclark@...il.com,
        robdclark@...omium.org
Cc:     viresh.kumar@...aro.org, sboyd@...nel.org, mka@...omium.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v6 5/6] media: venus: core: Add support for opp
 tables/perf voting



On 6/18/2020 8:24 PM, Stanimir Varbanov wrote:
> Hi Rajendra,
> 
> On 6/15/20 3:02 PM, Rajendra Nayak wrote:
>> Add support to add OPP tables and perf voting on the OPP powerdomain.
>> This is needed so venus votes on the corresponding performance state
>> for the OPP powerdomain along with setting the core clock rate.
>>
>> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
>> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
>> Cc: Stanimir Varbanov <stanimir.varbanov@...aro.org>
>> Cc: linux-media@...r.kernel.org
>> ---
>> No functional change in v6, rebased over 5.8-rc1
>> Bindings update to add optional PD https://lore.kernel.org/patchwork/patch/1241077/
>>
>>   drivers/media/platform/qcom/venus/core.c       | 43 +++++++++++++++++---
>>   drivers/media/platform/qcom/venus/core.h       |  5 +++
>>   drivers/media/platform/qcom/venus/pm_helpers.c | 54 ++++++++++++++++++++++++--
>>   3 files changed, 92 insertions(+), 10 deletions(-)
>>
> 
> <cut>
> 
>>   
>> @@ -740,13 +740,16 @@ static int venc_power_v4(struct device *dev, int on)
>>   
>>   static int vcodec_domains_get(struct device *dev)
>>   {
>> +	int ret;
>> +	struct opp_table *opp_table;
>> +	struct device **opp_virt_dev;
>>   	struct venus_core *core = dev_get_drvdata(dev);
>>   	const struct venus_resources *res = core->res;
>>   	struct device *pd;
>>   	unsigned int i;
>>   
>>   	if (!res->vcodec_pmdomains_num)
>> -		return -ENODEV;
>> +		goto skip_pmdomains;
>>   
>>   	for (i = 0; i < res->vcodec_pmdomains_num; i++) {
>>   		pd = dev_pm_domain_attach_by_name(dev,
>> @@ -763,7 +766,41 @@ static int vcodec_domains_get(struct device *dev)
>>   	if (!core->pd_dl_venus)
>>   		return -ENODEV;
>>   
>> +skip_pmdomains:
>> +	if (!core->has_opp_table)
>> +		return 0;
>> +
>> +	/* Attach the power domain for setting performance state */
>> +	opp_table = dev_pm_opp_attach_genpd(dev, res->opp_pmdomain, &opp_virt_dev);
>> +	if (IS_ERR(opp_table)) {
>> +		ret = PTR_ERR(opp_table);
>> +		goto opp_attach_err;
>> +	}
>> +
>> +	core->opp_pmdomain = *opp_virt_dev;
>> +	core->opp_dl_venus = device_link_add(dev, core->opp_pmdomain,
>> +					     DL_FLAG_RPM_ACTIVE |
>> +					     DL_FLAG_PM_RUNTIME |
>> +					     DL_FLAG_STATELESS);
>> +	if (!core->opp_dl_venus) {
>> +		ret = -ENODEV;
>> +		goto opp_dl_add_err;
>> +	}
>> +
>>   	return 0;
>> +
>> +opp_dl_add_err:
>> +	dev_pm_domain_detach(core->opp_pmdomain, true);
>> +opp_attach_err:
>> +	if (core->pd_dl_venus) {
>> +		device_link_del(core->pd_dl_venus);
>> +		for (i = 0; i < res->vcodec_pmdomains_num; i++) {
>> +			if (IS_ERR_OR_NULL(core->pmdomains[i]))
>> +				continue;
>> +			dev_pm_domain_detach(core->pmdomains[i], true);
>> +		}
>> +	}
>> +	return ret;
>>   }
>>   
>>   static void vcodec_domains_put(struct device *dev)
>> @@ -773,7 +810,7 @@ static void vcodec_domains_put(struct device *dev)
>>   	unsigned int i;
>>   
>>   	if (!res->vcodec_pmdomains_num)
>> -		return;
>> +		goto skip_pmdomains;
>>   
>>   	if (core->pd_dl_venus)
>>   		device_link_del(core->pd_dl_venus);
>> @@ -783,6 +820,15 @@ static void vcodec_domains_put(struct device *dev)
>>   			continue;
>>   		dev_pm_domain_detach(core->pmdomains[i], true);
>>   	}
>> +
>> +skip_pmdomains:
>> +	if (!res->opp_pmdomain)
>> +		return;
>> +
>> +	if (core->opp_dl_venus)
>> +		device_link_del(core->opp_dl_venus);
>> +
>> +	dev_pm_domain_detach(core->opp_pmdomain, true);
> 
> Without corresponding changes in venus DT node we call pm_domain_detach
> with core->opp_pmdomain = NULL which triggers NULL pointer dereference.
> 
> I guess you should check:
> 
> 	if (core->has_opp_table)
> 		dev_pm_domain_detach(core->opp_pmdomain, true);
> 
> or
> 
> 	if (core->opp_pmdomain)
> 		dev_pm_domain_detach(core->opp_pmdomain, true);
> 
> 
> ... not sure which one is more appropriate or both are.

Thanks, I'll fix that up when I repost. Sorry I was out for a while so
haven't been able to reproduce the rpmh timeout issue you reported.
Will spend some time on it this week and see if I can reproduce it.


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