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Date:   Wed, 14 Sep 2022 21:23:01 +0000
From:   Matthias Kaehlcke <mka@chromium.org>
To:     Johan Hovold <johan@kernel.org>
Cc:     Rajendra Nayak <quic_rjendra@quicinc.com>, andersson@kernel.org,
        agross@kernel.org, konrad.dybcio@somainline.org,
        mturquette@baylibre.com, sboyd@kernel.org, johan+linaro@kernel.org,
        quic_kriskura@quicinc.com, dianders@chromium.org,
        linux-clk@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] clk: qcom: gcc-sc7280: Update the .pwrsts for usb
 gdsc
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References: <20220901101756.28164-1-quic_rjendra@quicinc.com>
 <20220901101756.28164-3-quic_rjendra@quicinc.com>
 <YxDYJ+ONryLROBhL@google.com>
 <YyF+5CQqcLQlXvzV@hovoldconsulting.com>
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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@quicinc.com>
> > 
> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
> > Tested-by: Matthias Kaehlcke <mka@chromium.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
I guess that isn't the correct signal.

https://patchwork.kernel.org/project/linux-arm-msm/patch/20220914053017.23617-1-quic_rjendra@quicinc.com/