linux-kernel - Re: [PATCH 3/3] clk: qcom: gcc-sc7280: Update the .pwrsts for usb gdsc

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Message-ID: <f58077fd-3d12-4094-7d46-e49f25e16033@quicinc.com>
Date:   Thu, 15 Sep 2022 18:59:36 +0530
From:   Rajendra Nayak <quic_rjendra@...cinc.com>
To:     Matthias Kaehlcke <mka@...omium.org>,
        Johan Hovold <johan@...nel.org>
CC:     <andersson@...nel.org>, <agross@...nel.org>,
        <konrad.dybcio@...ainline.org>, <mturquette@...libre.com>,
        <sboyd@...nel.org>, <johan+linaro@...nel.org>,
        <quic_kriskura@...cinc.com>, <dianders@...omium.org>,
        <linux-clk@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] clk: qcom: gcc-sc7280: Update the .pwrsts for usb
 gdsc


On 9/15/2022 12:55 PM, Rajendra Nayak wrote:
> 
> 
> On 9/15/2022 2:53 AM, Matthias Kaehlcke wrote:
>> On Wed, Sep 14, 2022 at 09:12:36AM +0200, Johan Hovold wrote:
>>> On Thu, Sep 01, 2022 at 09:04:55AM -0700, Matthias Kaehlcke wrote:
>>>> On Thu, Sep 01, 2022 at 03:47:56PM +0530, Rajendra Nayak wrote:
>>>>> USB on sc7280 cannot support wakeups from low power states
>>>>> if the GDSC is turned OFF. Update the .pwrsts for usb GDSC so it
>>>>> only transitions to RET in low power.
>>>>>
>>>>> Signed-off-by: Rajendra Nayak <quic_rjendra@...cinc.com>
>>>>
>>>> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
>>>> Tested-by: Matthias Kaehlcke <mka@...omium.org>
>>>
>>> Did you confirm that you actually hit the retention state?
>>
>> No, how would I do that?
>>
>>> IIUC, this series is equivalent to using ALWAYS_ON unless CX is actually
>>> powered off during suspend.
>>
>> The count in /sys/kernel/debug/qcom_stats/cxsd increses with each suspend,
>> however it also does that with the GDSC configured as ALWAYS_ON and with
>> Rajendra's "arm64: dts: qcom: sc7280: Add required-opps for USB" [1], so
> 
> hmm, that's really not expected. With my above patch and with the GDSC as
> ALWAYS_ON there is a cx vote in suspend preventing cxsd so the counter
> should not go up.

Perhaps you are missing '1b771839: clk: qcom: gdsc: enable optional power domain support'
in your tree?

> 
>> I guess that isn't the correct signal.
>>
>> https://patchwork.kernel.org/project/linux-arm-msm/patch/20220914053017.23617-1-quic_rjendra@quicinc.com/